# Keeping Aquarium Rocks Clean



## rphox2003 (Aug 30, 2018)

Hi,

I have a question about something that's bothering me. When I look at other people's online pics and videos of their tanks, the rock work (for the most part) seems nice and clean. But the rocks in my tank get dirtier and dirtier over time.

I do 30-50% water changes every week. The only solution seems to be taking them out for a good scrubbing, which can be a hassle. Any advice on keeping them clean is appreciated.

Juwel 1.2 meter / 350 liters
2 External Filters - 2500 lph
15 Tropheus moori Katato
6 Tropheus duboisi Halembe
1 Eretmodus cyanostictus Kasanga


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## DJRansome (Oct 29, 2005)

When did you set up your tank? Diatoms are common for the first year, but eventually they go away.

What are your test results for pH, ammonia, phosphorus, nitrite and nitrate?

Think in terms of 50% weekly as a minimum. Improve water quality if indicated by your test results. Feed less. Restrict light. With the right balance, and after diatoms have left they will stay reasonably clean without fishkeeper intervention.


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## Ralph493 (Dec 1, 2018)

rphox2003 said:


> Hi,
> 
> I have a question about something that's bothering me. When I look at other people's online pics and videos of their tanks, the rock work (for the most part) seems nice and clean. But the rocks in my tank get dirtier and dirtier over time.
> 
> ...


I feel your pain. I could cut my tank maintenance by a lot of it wasn't for diatoms hopefully yours will clear up. My tanks are well over a year old. I've adjusted !ight, feeding and do regular tank maintenance. I do have high phosphate. I've used phosguard with no change. All the standard advice hasn't worked for me. So I scrub them every few weeks. On odd weeks I turn the rocks over saved a little time. Good luck


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## DJRansome (Oct 29, 2005)

Agree Ralph, it is unusual IME to have phosphate in your tap water. Hopefully rphox will have phosphate = zero.


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## rphox2003 (Aug 30, 2018)

DJRansome said:


> When did you set up your tank? Diatoms are common for the first year, but eventually they go away.
> 
> What are your test results for pH, ammonia, phosphorus, nitrite and nitrate?
> 
> Think in terms of 50% weekly as a minimum. Improve water quality if indicated by your test results. Feed less. Restrict light. With the right balance, and after diatoms have left they will stay reasonably clean without fishkeeper intervention.


I've been in cichlids (Malawi/Mbuna mostly) for over 10 years. About 10 months ago, I cleaned out my tank and switched to Trophs because I always wanted to give them a shot. I've had problems with dirty rocks in all my tanks, though, I even have two beautiful white Texas Holey Rocks but had to stop using them because they turned brown after a month or two.

I only turn on the light (LED) for 2 or 3 hours in the evening and the tank gets no direct sunlight.

Sorry but I've never tested my water. Never saw the need as I've never had sick fish or die offs.


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## DJRansome (Oct 29, 2005)

Well now you know what to do if you choose to.


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## rphox2003 (Aug 30, 2018)

Just to satisfy my own curiosity, I bought test strips.

Here are the results:
pH: 8.5
KH: 120 ppm, 6.6 dH
GH: 300 ppm, 16.8 dH
TC: 0.6
Nitrite: 0
Nitrate: 20

I also talked to my lfs who said it's natural from fish waste and happens over time to all tanks. I guess I'll just have to clean the rocks and change the gravel every so often.


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## DJRansome (Oct 29, 2005)

That is not true. First you need to know if you have phosphates. Second you are due for a 50% water change to get your nitrates down to 10ppm. Yes the LFS and API will tell you 40ppm is safe, but do you want to be just safe, or have limited algae?

Third you need to manage light. With no light you will have no algae. Not talking total darkness but no tank light and no direct sun light.

Finally, algae on glass and rocks is normal, but substrate is another story. Is this a new tank within the last 12 months? Brown algae (really diatoms) does get on substrate, but other healthy types of algae are usually glass and rocks.


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## rphox2003 (Aug 30, 2018)

DJRansome said:


> Second you are due for a 50% water change to get your nitrates down to 10ppm.
> 
> Not talking total darkness but no tank light and no direct sun light.
> 
> Finally, algae on glass and rocks is normal, but substrate is another story. Is this a new tank within the last 12 months? Brown algae (really diatoms) does get on substrate, but other healthy types of algae are usually glass and rocks.


I just did my weekly vacuum and water change and KH is up to 180 and Nitrates are 10.
The tank has no direct sunlight at all. The room is more or less dark all day while we're at work, and I turn on the tank light for no more than 3 hours a day.

I have very little algae on the glass, usually just in the corners which I clean every week.

The tank is now just over a year since my switch from Mbunas to Trophs. My light substrate has gotten darker (shades of greens) since I was forced to let the tank sit without fish or water changes for 5 weeks but the filters were running. But I think my the rocks are fish waste. I'll probably switch out the gravel and clean the rocks within the next month or so - working from home because of the virus saves me commute time. 8)


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## Fogelhund (Dec 3, 2002)

I wonder, is this a form of algae growing on the rocks, or diatoms? Maybe a picture would help?

If you've got Tropheus, growing algae on the rocks is extremely healthy for them.


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## rphox2003 (Aug 30, 2018)

Fogelhund said:


> Maybe a picture would help?


During the water change today, I rearranged the rocks. The rock on the upper right, I took out and cleaned so you can see the difference. In the very center of the pic you can see a clean area on the rock that had another one on top of it. You can also see the different shades of the substrate, which used to be light pinkish hues.

IMG_20200320_181433
IMG_20200320_181340


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## Fogelhund (Dec 3, 2002)

I'd recommend leaving the rocks alone, and stop cleaning them altogether. Your tank will be healthier for it.


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## BlueSunshine (Jul 13, 2014)

Fogelhund said:


> I'd recommend leaving the rocks alone, and stop cleaning them altogether. Your tank will be healthier for it.


^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^He knows something^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Good to see you back.


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