# Water Change System on Existing Rack... Ideas?



## svaqua1 (Aug 20, 2013)

I have a rack of tanks for my Cichlids... the tanks are ALL ACRYLIC, so very easy to drill. They are all set up now, and I have tanks to move the fish into and need a more efficient way of water changing... it just takes too much time with 70 tanks on this rack (multiple tanks with dividers). I was thinking of drilling the tops of the tanks and adding a bulk head with a strainer for an overflow, plumbing each one into a larger PVC drain pipe - maybe 3 or 4" in diameter, thru the wall into the back room with a drain in the floor.... That's seemingly the easy part here.

The hard part is this. How to make a manifold or some design where water can be put into the system daily to do an overflow style change... Each divided section is between 22-28 gallons, so I would want to do about 2-3 gallons per day to each tank and placing the input furthest away from the overflow. Problem: I have an inline hot water heater which can produce constant hot water for 10+ hours a day easily, but it needs a certain pressure commanded thru the unit to turn on (I think its like 3 or 4 gallons per minute) so the constant drip system would not be ideal, as only cold water would come in. Going tank to tank filling as it overflows is the same work as the old fashioned way, so ideas please?


----------



## Deeda (Oct 12, 2012)

Welcome to C-F!

You have the right idea on using the bulkhead fittings (BHF) to drain the tanks to a common main PVC drain. Are your individual divided sections separate from each other or do they flow through each other with perforated dividers?

Are you using sponge filters to filter the tanks? If so, how do you have the air distribution system set up? I ask this question because if you are using a PVC manifold with individual air valves to supply the sponge filters, this would be a similar way to add water to the aquariums.

How are you heating the tanks and what is the average temperature? You could do a simple constant cold water drip into the tanks if you are heating the aquariums. This should still keep the tanks warm enough as the heater(s) should maintain the proper temperature if the constant cold drip (depending on the drip rate) shouldn't impact the overall tank temperature.

You could also get fancier with the water change set up and install a system similar to landscaping irrigation. A timer controlled water mixing valve, connected to hot/cold water, would probably work with the tankless water heater system but you will need to crunch the numbers to determine the total number of 'new' water outlets to each tank you will need and then calculate the size of those outlets for the percentage of 'new' water you want to add AND the minimum flow requirements of the tankless water heater.

A bit more info about your particular set up may be helpful in moving this project along. If all your aquariums are located in one room, this will make planning everything much easier. Close access to existing water and sewer lines will definitely help. Are you on city supplied water or do you have a private water system? If on city water, you will need to consider pre-treatment for chlorine or chloramine that your provider adds to the system. Heating a well insulated room will also be more efficient than heating individual tanks.

Do you have any pics of your existing setups?


----------



## svaqua1 (Aug 20, 2013)

Deeda,

The tanks are divided solid and we use our own form of a whole wall sponge filter. You're from Medina, so you've probably been to where I am talking about but cannot mention since we don't sponsor here. We have 400 aquariums and are looking for a way to really make changes easier. The tanks are located in mostly one room, and the whole building is climate controlled to 80 degrees.


----------



## Deeda (Oct 12, 2012)

Yes I have been there and I'm familiar with your set up.

I would think that a constant cold water drip wouldn't impact the individual tanks depending on the drip rate. Another option might be to have a large coil of PEX or similar tubing place near the ceiling, where it's warmer, that would act as a pre-warming unit for the incoming cold water supply.

Do you know what the average incoming raw water temperature is? I know there are various formulae to figure out the heating requirements to raise the water temperature X number of degrees but the math really makes my head hurt.


----------



## svaqua1 (Aug 20, 2013)

I will have to find all that out... Right now we're gearing up to drive to Florida for MACNA, so this week isn't good to do that type of stuff


----------



## Deeda (Oct 12, 2012)

I've been thinking about this for awhile because I have a similar situation with a tankless water heater but only have a rack of 20 tanks that will be using a drip system OR an auto water change, I haven't decided which to use.

You need to determine what the minimum flow rate for the tankless unit is, many units are 5 GPM or less. You also need to determine how much cold water needs to be added to the hot water to bring the water change water to the correct temperature for the tanks. Obviously, the hotter the HOT water is, the more COLD water needs to be added thereby reducing the flow output of the tankless unit.

For my current water changing procedures for individual tanks, I lower the tankless unit to 100°F (the minimum setting), open the HOT tap on the faucet fully and then open the COLD tap until my digital thermometer reads 78°F. I then dispense the fresh water to the aquarium using a 3/4" hose with a PVC J-tube that hangs on the tank and has a ball valve so I can shut off the water when needed. I'm sure you are using the same basic procedure for your current water changes.

I think the key to determining how you need to setup your system will depend on the drain size you will be using on the aquariums and the total number of aquariums that would be on each segment of the auto change system. If you will be doing ALL the tanks at the same time, you may just need to adjust the temperature setting of the tankless water heater to achieve the desired temperature of the 'new' water.

I hope this makes sense.


----------



## Tyler_James_L (Jun 19, 2013)

I didn't end up reading your whole post because I have to go right now, but look up "aquarium water change drip system." Easy to do and effective.


----------



## Tyler_James_L (Jun 19, 2013)

ALRIGHT NOW! I see what you said. A hot water drip system is not necessary. If you have the proper sized aquarium heater, it should not be an issue. If your water is extremely cold, you can just have it go into a bin first and heat up to room temperature then go into the tank.


----------



## svaqua1 (Aug 20, 2013)

The whole building is heated... with 400 aquariums in it. Heater per tank is not possible the way we're set up. It is all acrylic, so the heat transfer is much nicer than that of glass...


----------

