# Problems keeping pH stable during W/C



## PlantFishMan (Oct 12, 2015)

About every 5 days I do a 20-25% W/C on my 75g AC tank. Ph b4 ~8.35 after ~8.0. It takes about 30hrs. to get back to 8.3+. During W/C change I make a solution in a gallon jug of 2 scoops Microlift pH buffer 8.5 plus 3-4 tsp. of baking soda and a tsp. of seachem rift lake salts. I slowly add this solution to the new water being added and with all that buffer pH continues to drop. Yesterday since my NO3 was about 30ppm I did a 40% W/C and added the amount of buffering solution as mentioned before. Within 1/2 hour pH went to 8.1. I added another scoop of Microl. pH 8.5 ( 1 scoop is suppose to be good for 30 gallons) and another 1.5 tsps. of baking soda. Within about 2hrs. - around midnight the pH was 7.99 - 8.01! As of now 5:50pm Ph is 8.16. *Note substrate is Eco complete African cichlid sand, and am using an American Marine Pinpoint pH monitor, probe is only 2 months old and I re-calibrated it 2 days ago. TDS is 260+ . pH from tap is ~7.2 - 7.4, moderately hard water. Can't understand why pH drops so much after a w/c even after I use a ton of pH buffer and lake salts. Is this pH fluctuation bad for fish? Haven't noticed any erratic behavior. Fish are : P. flavus, P. socolofi, P. saulosi, Iodotropheus sprengerae, Yellow labidichromis, Julie. marlieri, and synodontis petricola - dwarf. Any help greatly appreciated!


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## zimmy (Aug 13, 2010)

PlantFishMan said:


> Is this pH fluctuation bad for fish?


Yes. That's why most fishkeepers recommend you don't mess with the water chemistry. It's better fish don't have the ideal pH than one that constantly fluctuates. What you're experiencing can sometimes be the outcome of trying to control the chemistry.

What is the KH of your tap water?


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## LeeAberdeen (Sep 4, 2014)

+1

My tap water is exactly the same pH out the tap as yours, and I buffer one tank but not the other. Call it an experiment. The smaller tank's buffered to 8.0 or slightly above, the KH to 18, but the larger tank's stays constant around 7.2.

I can honestly say they're as healthy in the larger tank with a pH which is not seen as ideal as they are in the buffered tank. The key is consistency because, as you hinted, a fluctuating pH is unhealthy for them.

I got them from a well-respected breeder who kept them at the same pH as my unbuffered water, which made the decision not to buffer straightforward.

I wouldn't get caught up in buffering. The only reason I buffered the smaller tank is because the water board did work on the supply and the pH crashed, killing four of my labs before I realised. They'll be fine with 7.2-7.4. Mine breed like crazy at that.


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## PlantFishMan (Oct 12, 2015)

My KH from tap is ~3-4dh ( great for my planted tank), the problem is even if I don't add any buffer during w/c the eco complete sand is buffered for around 8.2- 8.3. So even if I don't add buffer after w/c and wanted to keep it near my tap pH it's still going to slowly ( about 48 hrs.) rise to that level. Unless there's another way to keep pH close to my tap water, for stability I would have to remove the substrate and replace it with a neutral one - which I really don't have the money to do or any other place to keep my fish - I have 28 total all juveniles. What I don't understand is why the pH still drops significantly when refilling from a w/c especially when adding a LOT of buffer including baking soda.


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## DJRansome (Oct 29, 2005)

I never had that experience (aragonite or crushed coral keeping my tank at pH>8.0. My pH=7.8 in spite of aragonite and crushed coral for over 10 years.


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## zimmy (Aug 13, 2010)

PlantFishMan said:


> What I don't understand is why the pH still drops significantly when refilling from a w/c especially when adding a LOT of buffer including baking soda.


How heavily is your tank stocked? What's your filtration system? How often do you clean your filters? What is your nitrate reading before water changes? All of these things can cause your pH to drop.

Have you tested the impact of your substrate on your tap water? I agree with DJ. I've never heard of the substrate having that much impact on water chemistry.

My recommendation would be to stop using all the additives and get your water chemistry stabilized again by making a series of small water changes over several days with nothing but dechlorinator added. Eventually your tank water should stabilize. That's what you want.


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## PlantFishMan (Oct 12, 2015)

When I setup the tank a little over 2 months ago for the first week the pH was hovering around 7.5 - 7.8. I called Seachem and told the rep that their packaging for Eco Complete African sand said it would keep the pH @ 8.2 - 8.3, but the rep said it would take awhile for it to reach that level - a week or two - once at 8.2 - 8.3 it will stay there, if the pH goes below that more of the sand will dissolve until it reaches the latter levels. But now after reading some old posts here and on MonsterFish it seems the best approach would be smaller more frequent w/c's - like you said zimmy - to stabalize the pH. Maybe 10 - 15% every 3-4 days, instead of 30-40% every 5-6 days; FYI : 4" substrate, 28 fish ( juveniles), Aquatop CF500UV canister with 2 bags of Chemi Pure ( since I only set it up 2 months ago haven't cleaned it yet), Fluval C3 HOB with 100ml sachet of purigen, Koralia Evolution circ. pump - 825gph - , air stone on 24/7, 14 bunches of Valls, 12 bunches of Anubias, been adding 2 capfuls of Seachem cichlid trace per week and 1 to 2 capfuls of Flourish plus have several flourish tabs underneath the valls. Feedings 2x/day: am- spiralina flakes & Hikari mini wafers in pm alternate each day with spira. flakes or hikari spiralina frozen brine shrimp/SF blood worms. Did 40-50% w/c couple of days ago because NO3 was~35ppm (*last time I checked NO3 levels was about 2weeks ago and it was ~15ppm). Thats' when everything happened as mentioned in first post.


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## PlantFishMan (Oct 12, 2015)

Made mistake about TDS value it's 160+ not 260.


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## somebody (May 13, 2014)

+1 on the crushed coral. I've had about 10 lbs in the bottom of my sump since day one. Tap is 8.2 and tank maintains 8.2. It's perfect. I also have large pieces of limestone for aquascaping so I'm willing to bet that's helping. Another thing, my water change schedule is only once every 3 weeks (not by choice, job keeps me from home) and I (meaning the wife) tests it about 2 times a week while I'm gone and I have no flutuations what so ever. Crushed coral is the way to go in my book.


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## zimmy (Aug 13, 2010)

somebody said:


> +1 on the crushed coral. I've had about 10 lbs in the bottom of my sump since day one. Tap is 8.2 and tank maintains 8.2. It's perfect. I also have large pieces of limestone for aquascaping so I'm willing to bet that's helping.


Maybe. What's the KH of your tap water? It also makes a difference that your tap water's pH is already 8.2. Having a sump also means you likely have a larger volume of water in your system relative to the bioload.

I'm not against using crushed coral/aragonite. I don't think they make that much difference. My concern is about using a bunch of additives that cause pH to be wildly unstable as the OP is experiencing.


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## wortel87 (Apr 15, 2014)

Tap water should rest a little while to get a good ph reading. It has to gass of.

If I take a reading straight from the tap I also get 7.2 after 15 minutes rest its arround 8. my tank is arround 8.

Dont mess with it and dont worry about it. Your kh will flatten it out enough. Never gave me any problems what so ever.

Its when your altering your tank water and add totally different water when things go wrong.


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## PlantFishMan (Oct 12, 2015)

Don't know if this will help. Tonight tested KH & GH in my tank & tap. Tank : KH - 270ppm = 15dh , GH - 100ppm = 5.6dh ; Tap : KH - 40ppm = 2.2dh, GH - 100ppm = 5.6dh ; pH of tap water after 24hrs. = 7.3. Will do a small w/c ( 10-15%) tomorrow and just use dechlorinator -Prime - and let you know what happens to pH.


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## PlantFishMan (Oct 12, 2015)

Forgot to mention test kit used was Hagen Nutrifin.


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## PlantFishMan (Oct 12, 2015)

here is a quote from cichlid expert Dr. Paul Loiselle when responding to a person who had crushed coral in his AC tank where pH from tap was ~ 7.4 and his coral would push it up a little higher after w/c. *note this person said he was doing "frequent partial W/C's". * What is far more critical to successful husbandry of rift lake cichlid fish is proper nitrogen cycle management. These cichlid fish are extremely intolerant of ammonia and nitrite. The program of regular partial water changes you presently practice may depress the pH in your aquarium somewhat, but its contribution to the well being of your fish far exceeds any imaginable benefits from a higher pH. Your management practices are exactly those I would recommend to a prospective rift lake cichlid fish aquarist. Just keep up the good work and don't lose any sleep over those pH values.*


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## somebody (May 13, 2014)

> Maybe. What's the KH of your tap water? It also makes a difference that your tap water's pH is already 8.2. Having a sump also means you likely have a larger volume of water in your system relative to the bioload.
> 
> I'm not against using crushed coral/aragonite. I don't think they make that much difference. My concern is about using a bunch of additives that cause pH to be wildly unstable as the OP is experiencing.


I've never tested the tap water good point though. My tank kh is 18, I'm sure that if the cc wasn't in the tank the ph would slowly creep up. Before I sumped the tank and did a major overhaul on it ( broke it down and recycled) I had flagstone I would test ph it would bounce back and forth after wc it would be 8.2 but a week later it would be 7.6ish. When I sumped it I added the cc and since then I never saw a fluctuation with the ph. About 2 months after that i added the 150 lbs of limestone. That's when I started monitoring the kh so no real difinitive answers on how the limestone or cc helped the kh but it did maintain ph. Good enough in my book


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## PlantFishMan (Oct 12, 2015)

Since the GH in tank ( and tap) is a little low - 5.6dh - over the next several days I'm going to add some Epsom Salt in small quantities until I can get it up to 10-12dh, then maybe I won't have a moderate pH swing when doing w/c's.


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## BC in SK (Aug 11, 2012)

I think you should take this advice as well:


PlantFishMan said:


> here is a quote from cichlid expert Dr. Paul Loiselle when responding to a person who had crushed coral in his AC tank where pH from tap was ~ 7.4 and his coral would push it up a little higher after w/c. *note this person said he was doing "frequent partial W/C's". * What is far more critical to successful husbandry of rift lake cichlid fish is proper nitrogen cycle management. These cichlid fish are extremely intolerant of ammonia and nitrite. The program of regular partial water changes you presently practice may depress the pH in your aquarium somewhat, but its contribution to the well being of your fish far exceeds any imaginable benefits from a higher pH. Your management practices are exactly those I would recommend to a prospective rift lake cichlid fish aquarist. Just keep up the good work and don't lose any sleep over those pH values.*


I'm not sure why there is so much focus on pH. As a reflection of water quality, Nitrogen is really where it's at. What ever allows you to do more water change, is likely going to benefit your fish. 


PlantFishMan said:


> Since the GH in tank ( and tap) is a little low - 5.6dh - over the next several days I'm going to add some Epsom Salt in small quantities until I can get it up to 10-12dh, then maybe I won't have a moderate pH swing when doing w/c's.


KH is connected to pH level, but GH not so much. Your GH at 5.6dH is right in the range of lake Malawi http://www.cichlid-forum.com/articles/lakes_east_africa.php Total hardness of 4-6 dH. I know the common recommendation is to keep Malawi cichlids in 2-5x harder then lake Malawi, but it is really unnecessary IMO. ( Not exactly sure why and how these recommendations came about but I have my theories). Though I think GH is typically a more important water parameter then pH.
Unless there is agricultural run-off, most bodies of water, in terms of ppm, are 0 for nitrate. Nitrogen is a limiting nutrient that gets used up quickly. Aquariums are almost always much higher in Nitrogen, then natural bodies of water. If you are really trying to replicate lake Malawi water you should focus on the more important water parameter: Nitrogen. Additives usually make it more difficult to change large amounts of water and keep nitrate in check. And I think, what ever affect your substrate has on pH would be very slow and gradual.


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## PlantFishMan (Oct 12, 2015)

Did a 50% w/c yesterday due to high nitrates - ~40ppm - pH b4 w/c = 8.21 ; added a ton of microbelift pH up 8.5 (3x rec. dosage), some epsom salt and 3x dosage of rift lake salts in solution and added to new water being added. Within 1hr. of w/c pH was down to 7.9 and in 2hrs. 7.86 - bottomed out there. Today @ 6pm pH is 8. Don't understand why this happens when adding 3x the buffer needed. Nitrates are below 20ppm and fish appear to be ok.


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## BC in SK (Aug 11, 2012)

You appear to be doing opposite of the advice you are being given. This is essentially the same advice as the quote from Paul Loiselle:


zimmy said:


> My recommendation would be to stop using all the additives and get your water chemistry stabilized again by making a series of small water changes over several days with nothing but dechlorinator added. Eventually your tank water should stabilize. That's what you want.


Instead your using 3x the recommended dosage......and still wondering why pH is not stable when you are trying to alter it with additives. A fairly stable pH 7.2-7.4 would likely be far superior and a lot less trouble.


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## PlantFishMan (Oct 12, 2015)

Yes a 7.2- 7.4 ph if stable would be great. But because of the CaribSea Cichlid sand it eventually pushes the pH back up to 8.2. So just using dechlorinater with the small w/c's will make the ph drop to 8 or below as previously stated and then it slowly creeps back up to 8.2. So because of this i am not getting a Stabile pH. Unless a .3+ difference within a few hours isn't that bad as long as there are no ammonia/nitrites?


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## BC in SK (Aug 11, 2012)

PlantFishMan said:


> Yes a 7.2- 7.4 ph if stable would be great. But because of the CaribSea Cichlid sand it eventually pushes the pH back up to 8.2. So just using dechlorinater with the small w/c's will make the ph drop to 8 or below as previously stated and then it slowly creeps back up to 8.2. So because of this i am not getting a Stabile pH. Unless a .3+ difference within a few hours isn't that bad as long as there are no ammonia/nitrites?


Well maybe I am missing something (?) but based on your first post, my understanding is that you have always been using the additives. Takes a little time for the buffer to do it's job. I think you are giving far too much credit to the substrate, when the swings in pH really point to the additives you are using!
I would think if you started with declorinated tap water ( minus the buffers and "cichlid salts"), that the substrate would have very slow and minimal affect on pH. Of course now that you have been using additives, it will take a few water changes to bring it down to a value closer to your tap water.


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## BC in SK (Aug 11, 2012)

PlantFishMan said:


> But because of the CaribSea Cichlid sand it eventually pushes the pH back up to 8.2.


Just a thought. How about you perform a small experiment. Place a small amount of this substrate in a small container. About equivalent proportion as you have in your aquarium. Add nothing but tap water (declorinator if you like). Monitor pH over a weeks period and see just how much and how quickly the substrate affects pH.

Your aquarium already has high KH from the additives you have been using. Your tap water has low KH and lower pH. I think at this point, given your tap water, the only way you could continue using additives and not get some fluctuating pH, is to pre-mix your water and let it sit until it is similar to your tank water. That would make water changes a real PITA, IMO. How serious are the fluctuations that your tank is experiencing at every water change? I really couldn't say. But I think it preferable that your tank would be closer to your tap water, to facilitate large water changes with out a lot of fluctuating water chemistry.


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## jcabage (May 29, 2012)

BC in SK said:


> PlantFishMan said:
> 
> 
> > But because of the CaribSea Cichlid sand it eventually pushes the pH back up to 8.2.
> ...


This would be really interesting.

We toss the phrase "buffer to" around a lot. Isn't a buffer, by definition, a means of maintaining stability? It would seem that if your pH is swinging in general, the sand, etc. is doing a poor job of buffering anything. When you add chemicals, etc. to your tank to raise the pH, you aren't buffering the pH, you are altering it, IMO.

I've never noticed increased pH stability in our tanks because of limestone, aragonite, etc. I've also been consistent in not altering our pH intentionally.

A buffer would seem to be most helpful in the situation described above, where your tap water was altered before leaving the pipes, and water with a wildly different pH than your normal tap was used to fill the tank. Then hopefully that buffering material would keep the tank from swinging out of control.


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## PlantFishMan (Oct 12, 2015)

*"Just a thought. How about you perform a small experiment. Place a small amount of this substrate in a small container. About equivalent proportion as you have in your aquarium. Add nothing but tap water (declorinator if you like). Monitor pH over a weeks period and see just how much and how quickly the substrate affects pH."*
Already done this used a 20 gallon high that I'm going to use for a breeding pair from the 75. Used 2.5" Caribsea cichlid sand filled with water and dechlorinated with Prime. Used PinPoint pH monitor with probe ( calibrated probe 1st), pH = 7.56, Day 2 = 7.61, Day 5 = 7.8, Day 7 = 8.1. By day 9 reached 8.21 and stayed there. Performed a 20% w/c today and just used Prime, within 1/2 hr. after w/c pH = 7.79.


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## Deeda (Oct 12, 2012)

Can you do a similar experiment as above with no substrate? It doesn't need to be an aquarium, just use a clean glass container.

I haven't checked your other posts specifically but do you test your KH (alkalinity) at all?


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## PlantFishMan (Oct 12, 2015)

Yes I check KH using a colorimeter . Tank = 275ppm ~ 15.4dh ; Tap ( dechlorinated) = 40ppm ~ 2.2dh ; GH in both tank & tap is 100ppm ~ 5.6dh.


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## Deeda (Oct 12, 2012)

Interesting! Leave the tap water set out and check it daily over the next few days. I'm guessing you will see the KH rise, just like in the aquarium.


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## PlantFishMan (Oct 12, 2015)

OK will do - just put some dechlorinated tap water into a jar and KH is 5.5, will check again tonorrow. FYI performed a 15-20% W/C on the tank last night adding nothing but dechlorinator , pH went from 8.10 to 7.84 about 3hrs. after w/c. Today as of 7pm pH is 8.06.


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## PlantFishMan (Oct 12, 2015)

a few hours ago added 3/4 gallon of dechlorinated tap water to replace evaporation. B4 adding pH was 8.05 after 3 hrs. pH is 7.94. The jar of tap water set aside yesterday - today Kh is 5.4dh.


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## PlantFishMan (Oct 12, 2015)

Today the water in the jar's KH is 5.2. Doesn't seem to be going up like Deeda thought it would. I'm very puzzled.


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## Deeda (Oct 12, 2012)

Thanks for keeping up with the jar readings. I am a bit confused though because your post on 1/12 your tap water w/dechlor was 2.2dH for KH. Your post on 1/13 the jar tap water w/dechlor was 5.5dH for KH. I would have thought these numbers would have been the same since they were treated the same. Is the jar water open to air or is it sealed? It's supposed to be open to air.

Could you also check the pH of the jar water for us?

Usually when trying to troubleshoot increases and decreases of pH, GH and KH between tap (source) water and aquarium water, doing my suggested experiment will show some changes in at least one of those parameters. Though I will admit that the experiment was supposed to have the sample test aerated constantly, usually by an air line.

I need to go back and read your thread from the beginning to see if something was missed.


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## PlantFishMan (Oct 12, 2015)

Ph of jar of water is 7.2, will add a small air stone to it now and let u know pH tomorrow night. Don't understand the discrepancy of the Kh between 1/12 & 1/13. I'll test the KH of the jar and tap water again tomorrow night. If it still says <5.5dh will start over again with a different clean, dechlor. jar of water and this time add an airstone at the beginning of the test.


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## PlantFishMan (Oct 12, 2015)

Realized with colorimeter instrument test vial needs to be perfectly clean inside/out. Earlier KH tests vial was not completely clean, SO starting tonight with a quart jar of dechlorinated tap water with an airstone. Starting pH = 7.35; KH = 80ppm = 4.48dH. Will report same time tomorrow night.


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## PlantFishMan (Oct 12, 2015)

As of 11:30pm last night jar of dechl. tap water, 24 hrs. w/air stone : pH = 7.30 ; KH = 75ppm ~ 4.2dh


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## PlantFishMan (Oct 12, 2015)

Tue. night jar of water ; pH = 7.0 ; KH = 60ppm ~ 3.36 ; Tonight p = 6.9 , KH = 57ppm ~ 3.2 ; Looks like pH & KH going down instead of rising. :-?


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## Deeda (Oct 12, 2012)

Thanks for keeping up with the test sample over the last few days.

I can't find the article that gives a great explanation of why pH and KH drop over the course of a few days in the test sample. I've been looking for it but I lost all my bookmarked articles and don't want to guess at it.

In the aquarium these values can drop due to the amount of waste present in the tank. Looking back over your initial posts, the substrate you are using appears to be keeping the pH and KH high, at least according the the mfg. claims but it does take a few days to 'bounce' back after a water change.

As suggested by other members, the addition of the buffer products is a pain to be doing at water changes and you are trying to get 'perfect' results immediately. I'm not faulting you on this, many people get over wrought trying to get ideal water parameters.

From your other post you said "the Eco Complete African sand said it would keep the pH @ 8.2 - 8.3, but the rep said it would take awhile for it to reach that level - a week or two - once at 8.2 - 8.3 it will stay there, if the pH goes below that more of the sand will dissolve until it reaches the latter levels."

You've already done the 20H experiment with just water, dechlor and substrate and seen the results over a week and after a 20% water change. I don't think the pH difference after the water change would be too drastic for the main tank. The key is relatively stable parameters.

Hopefully someone else will chime in with a better explanation of the pH/KH relationship experiment.


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## PlantFishMan (Oct 12, 2015)

Forgot to mention bought Seachem's Malawi/Victoria buffer and did a 15% pwc this past sunday. Instructions on the buffer says it will maintain pH between 7.8 - 8.2 when used as advised : 1 tsp. per 10-20 gallons once you get the pH you want, then add every 2-3 weeks to maintain ( they're basing that on a 20-25% pwc every 2-3 weeks). If you want a higher pH - closer to the 8.2 limit - add a little extra. So when I did the water change pH b4 = 8.09; about 6hrs. after ( mixed in 2.5 tsp. of M/V buffer) pH bottomed out at 7.87 then over next 24 hrs. rose to ~ 8.11. So I think this buffer is helping after pwc since pH is only dropping by 0.2 instead of .4 or more when using baking soda or just dechorinated tap water. Thru all this fish appear healthy, they are eating and my male P. socolofi paired with a female and are setting up a nesting area, but no fry yet. So I think my problem is basically solved for now. Thanks everyone for your help. Will let you know if anything changes.
One more thing added hornwort to tank with Valls ( for some reason 7 out of the 12 buches aren't growing that much) & anubias that were already there to soak up the nitrates ( 30-40ppm), also might add a small nitrate reactor.


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