Automatic water changes on 25 gallon

[sammer]

I am considering seting up and automatic water change system for a 25 gallon tank with sump.

Would this be a really bad idea for a small system?
I would use my apex controller with float switches and temp monitors etc for the NSW bucket.

I would also use just two small pumps for adding and removing water (about 1 gallon per min)

Any thoughts

Thanks

[Cal_stir]

How will you monitor your NSW so you don't accidentally do a WC if the salinity isn't correct or the NSW tank is empty?

[NanoCat]

If I were to do this:
I would use a float switch in the nsw to stop the process if there is not enough water and possibly use a salinity probe to check the salinity or just manually check it with my refractometer every few days. The mix up water I use now barely evaporates (no salinity shift) covered 5 gallon bucket over a weeks time anyways so as long as the batch it the correct salinity it should be ok.

I would also use a temp probe and a heater to match exactly the dt temp.

[sammer]

This is essentially what I would do Nanocat.

Does anyone see any problems with this or have suggestions. I would plan on changing about a 1/2 gallon or so every day.

[fishytime]

methinks it would be a mighty fine balancing act.....trying to match flow rates of two different pumps will be tricky and I would suspect that you will be constantly adjusting and tweeking the times as the pump/hoses get dirty.....and then there is the "what ifs".....what if one of the pumps fail or doesnt start properly?....might be a flood or a return pump running dry waiting to happen.....that and mechanical float valves have been known to fail

[Reefie]

+1
Keep in mind that the pump that pumps water OUT will be more efficient due to gravity helping than the pump that pumps water UP and IN.

I had thought of doing something like this with my BC29, until I researched that. Too many variables to factor in to make it worthwhile.

Originally Posted by fishytime

methinks it would be a mighty fine balancing act.....trying to match flow rates of two different pumps will be tricky and I would suspect that you will be constantly adjusting and tweeking the times as the pump/hoses get dirty.....and then there is the "what ifs".....what if one of the pumps fail or doesnt start properly?....might be a flood or a return pump running dry waiting to happen.....that and mechanical float valves have been known to fail

[philg3]

I wouldnt DIY one because of the reasons mentioned above, but if I had the cash and really wanted auto water changes....

http://www.genesisreefsystems.com/categories.php?cat=7

[sammer]

It seems like this may not be the best idea.

I did not plan on just using two pumps on timers but rather use the apex controller to coordinate various float switches, pumps and monitors.

I would have the NSW water bucket running with a pump for circulation and a heater and heater probe to sync the temp with the DT. At a specific time my apex would shut down my ato outlet and tun on the pump in the sump until a low water level float switch was activated. I would also include a timed shut off that was only a few seconds longer that the time needed to pump out the osw and possibly a back up low float switch. Then after waiting a few moments a pump in the nsw would activate and fill the sump up to the best water level line in my tank which would be the same as the ato switch height. I would also use a back up timer that ran a few seconds longer in case the switch were to fail and also include a back up float switch. After the switch was tripped my ato would be turned back on again.

The system would only be changing maybe a 1/2 gallon per day and I could possibly use a salinity probe in the tank to monitor any possible salinity shifts to stop the process or set off alarms.

I have seen the Genesis water change system and it looks nice but don't see how it is less prone to failure and seems to make you change at least on gallon at a time.

Thanks for your responses.

Maybe this might not be a good idea but I have seen a few examples of system like this on the internet.

Do you all still think it would be a bad idea?

[steve fedyk]

I do a daily water change on my 120 reef and love it. I use pump from my basement, controlled by an Aqua jr to bring up the new water up for 1 min. In the sump I have a float switch on a timer and its on for about 15min a day, just in case of a power outage. My one problem was setting the float switch right. I solved this by using a magnetic probe holder to hold the float switch, easy to a just.

On a smaller tank I would use a dosing pumps to add and remove water. I would add the water first and then when its done, have the pump remove the water. I check my salinity about once very week or two.

[burgerchow]

Hmmm, 20% after change every 2 weeks is only 5 gallons. Seems like a lot of extra work and expense you're considering for such a small tank.
I would only consider an automated system for a tank over 100 gals