Automatic Water Change System

I've nearly completed assembling the PVC and by the end of the week plan on having it up and running!

My system consists primarily of a six foot long 3" PVC pipe filled with carbon (to remove the chlorine), a water timer (to schedule how much and how often I water is added), and a PVC overflow similar to the one I posted about here which goes under the house and into the yard.

As I add tanks for additional breeding groups I will be plumbing them into the same sump which means that this one water change system will service the entire fish room.

I will add pictures tomorrow.

Heh. Sorry, didn't actually think that many people would be interested. *grin*
I took some pics, but they didn't come out very well and I've done a lot of work since then, so I will beg everyone's forgiveness and take some new ones this evening. No, really...I will...honest!

So I deviated a little from my original plan, and now I'm paying the price. I've been going back and forth about putting the water shutoff timer before or after the carbon chamber. I was originally going to put it after the carbon, mostly because it has a second output valve which I could use to test the water for chlorine and if I needed a bucket of dechlorinated water.

Then I got to thinking that putting the valve after the carbon chamber would mean that the carbon chamber would be at street pressure all the time and wouldn't have anything between it and all of my houses chlorinated water. I'm sure that there wouldn't be much circulation, but I much preferred the idea of having the carbon chamber isolated from new water when not in use. So I moved the shutoff valve to before the carbon chamber without thinking about how I was going to perform chlorine tests and extract extra chlorinated water for my tank accross the house.

I'm heading by Home Depot later this evening to pick up two ball valves so I can put a T in the line right before the sump that will allow me to redirect the water into an outlet for testing.

Other than that, everything has come together nicely. It has really struck home how much carbon I'm going to need, so I'm printing off some prices from Drs. Foster & Smith to take to my local PetSmart since they do pricematching.

mvigor said:

So you're just going to do a chlorine test periodically and change the whole tube of carbon when needed? Do you have any numbers on ounces of carbon per gallon of water you're going to need?

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Correct. I can't say for sure, but I expect that the amount of carbon needed would directly relate to the chlorine level in the water. Also, if you push water through the carbon chamber at higher pressures I'd expect it wouldn't remove chlorine as well, but if you let the water trickle through and spend more time in contact with the carbon it should more thoroughly neutralize the chlorine.

mvigor said:

I'm asking because I have a HUGELY overstocked tank right now and it possibly will be until Jan./Feb. I am interested in a constant-flow trickle system to do WC for me.

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I thought about a constant flow, but I wasn't sure if that would be as efficient as small bursts periodically. I am hoping that by the time the newly added fresh water makes it's way through the system back into the sump, the water level will have already drained back down to normal and I wont be loosing fresh water as I add it.

Pictures (finally)

I promised pics, so here we are.

First, the brains and brawn of the operation. Below is the water scheduler and the top end of the carbon tube.

The main 3" pipe that is filled with carbon is secured to the wall by screwing a 2x4 into the studs along the back of the close, then strapping the pipe to the 2x4. One piece you can't see is the grates which I fitted inside the ends of the 3" pipe to keep the carbon from leaving the tube.

Here's a closeup of the parts used to conver the 1/2" CPVC to the 3" PVC.


And now for the sump.

I know, I should have tidied up a bit before taking the pic. On the far right you will see two pipes coming up from the floor. The farthest to the right in the corner is the incoming water line. At this point the water has been dechlorinated. You'll notice a T junction and two orange valves. This is so I can redirect the water into a tap for testing and to fill buckets with dechlorinated water for use in other areas of the house. The incoming line continues to the far left end of the sump. This is so the water enters just before being pumped up to the tank(s).

The second pipe coming up from the floor is the overflow drain. You can see the intake for the drain in the back right corner of the sump. Any time the water level gets above that point it drains out into the yard.
Here's a closeup of the plumbing in the corner of the room and of the overflow siphon system.


I put in a single bucket of carbon and tested the system only to find that it worked quite well at removing chlorine. I still plan on filling the rest of the tube and I expect it to last at least a year...probably much more.

mvigor said:

Awesome! Excellent job! I could have walked the aisles in Home Depot for four weeks and never been able to figure out the right way to make the connection you have pictured there. These pictures really say a lot! Congratulations.

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Thanks. Like most things, you just gotta take it one piece at a time.

We went camping this weekend and was pleased to come home to a thriving tank with no water on the floor or dead fish. My only complaint is that I probably shouldn't have used 1/2" CPVC for the sump overflow because it doesn't drain fast enough. It will do as long as there's no huge backwashes from the main tank.

I ran some numbers this evening. Please understand that these are VERY ROUGH ESTIMATES.

I started by timing how long it took for me to fill a 1 gallon jug at the current rate of my water change system. It took approximately 1 minute and 45 seconds.

That comes out to about 3 gallons during each five minute change (I bumped it up a bit to account for the carbon chamber filling with water and trickling out at the end of the water change).

Since I'm currently performing four of these changes a day (one every six hours), that comes out to around 12 gallons per day or 85 gallons a week.

So even given the large margin of error inherent in these figures, I think it's safe to say that my system as it's currently configured changes out at least 1/3 of the water every week.

I'm getting excited. Between such frequent and significant water changes and the plants I'm adding I expect it to be an ideal environment for breeding. :dive2:

I am also going to check into how much misters cost (like they use in greenhouses) to put on the end of my water change spout. It will give me a little bit more dechlorination just before entering the tank.