One way waterchange and combined frag/quarantine setup...
 

I recently set up a new frag/quarantine tank system in conjunction with an automatic water changer and wanted to see if others have tried this before and get people's thoughts on the following setup. I posted this on my local reef club's forum and there were some interesting and valid points raised regarding system complication and frag tank dilution of toxins... Below are excerpts from my prior posts as well as a diagram and some photos...

Jason

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Two weekends ago I set up my frag tank and my water changing system. With my new setup I knew I wanted a decent frag tank alongside my display tank. Additionally, I have always wanted a quarantine tank as well, but did not want to deal with the expense and hassle of maintaining two separate bodies of water. A separate quarantine tank would typically mean dual equipment setup and twice the testing, water management, etc.

In one of the "Tank of the Month" articles (don't remember which one), the author noted that he had set up a one way water changing system that took water from his display to a quarantine/frag tank and then to the drain. This allowed him to use his display tank water in his quarantine tank. Because the whole system is setup with peristaltic pumps, water only flows from the display to the frag tank. There is no risk of pests going from the quarantine tank to the display.

Because the frag/quarantine tank is significantly smaller than the display, changing a small percent of the display tank's water amounts to a large downstream percent change on the frag tank. This means one doesn't need to separately maintain the water parameters in the frag tank... thus, no need for a second skimmer, kalk reactor, calcium reactor, phosban/carbon reactor, etc. The only thing you really need in the frag tank is a heater.

My new frag/quarantine tank and water exchange system has been running for a couple of weeks now and I'm quite happy with it.

Here's a diagram of how the system works. You can step through the red numbers to follow the water flow.

http://jasonwong.smugmug.com/photos/...41_wWqMv-L.gif

Here's a photo of the frag/QT tank:

http://jasonwong.smugmug.com/photos/...08_T8hLE-L.jpg

Here's the back of the display tank and the frag/QT on the right:

http://jasonwong.smugmug.com/photos/...95_AWnDK-L.jpg

I have noticed that without an autotopoff on the frag tank that salinity does slowly creep up over time. I could add an RO autotopoff to the frag tank, but for now have managed the slight salinity changes with manual topoff of RO water once a week.

I think the key benefits of this system are:

1) Always having a QT tank on hand. I'm bad about quarantining and won't do it unless I have a QT system readily available. (I think this is the biggest benefit of the whole setup.)

2) Decreased overall equipment cost vs a "display plumbed to frag tank + QT tank setup)

3) Potentially decreased water maintenance issues... This remains to be seen. Theoretically I am hoping that because the water changes on the frag tank are so large (percent wise per week) that I don't need to maintain the water parameters (other than temp) in the frag/qt separately. If this isn't the case, then to be honest, it might not be worth doing it this way... will only know if this works with more time.

Thoughts?

If you simply fed your main display and let it overflow into the QT, you wouldnt have to mess with floats, Litermeters, etc. A timer, powerhead, and a small valve to adjust the flow to a trickle would be all you need:). You would still have to acct for the salinity in the frag tank though.

But I would have to overflow from the display sump into the QT, no? This would mean my QT would have to be lower than my sump which would be pretty inconvenient.

Perhaps there's a different way you're thinking of doing it?

True. In the pic, it looks like they are almost at the same level.

This is a great idea and is very much like what I was planning on implementing. Only for me, I was planning on diverting some flow from the return pump (controllable via a ball valve/union) to a combination frag tank and refugium. Then I was going to use a LM3 much like you are to take water and divert it directly to a small 20-30 gallon quarantine tank that then overflows to drain. I was just going to use a powerhead for flow and have a small heater in there. That way a quarantine tank is always available and will actually be used.

You could divert flow from your return to the frag tank which could overflow into your sump. You wouldn't even necessarily need a heater in there because it's cycling through your main system. Then possibly use your LM3 to divert flow to another tank that you could use as a QT that would always be available. Or maybe even partition your existing frag tank off for that purpose. Whatever fits best for your space.

Question ... if you use a combo QT/frag tank to treat fish and stuff, do you want the meds to also be in there with your frags? I suppose your partition would kinda serve as a 1-way path for water where you could just medicate the last section. Some may cross over, though, depending on turbulence from powerheads ...

I cut a 75 down and my frag tank looks pretty much the same as yours. I had the same idea of a small daily water change with the waste water going to the frag tank to flush that system with display water. I love the idea of less equipment and being able to QT and medicate that tank. The pumps are friggin expensive though. Right now I'm manually changing 4 gal a day from my sump to the frag tank. Randy Holmes-Farley uses the Reef Filler pump to auto change a daily amount that would work perfectly for this application. I'll be tagging along for this one as I try to tweak my own similar setup...

I know this is very old but anyone still using this idea?

I’m considering doing this. I have a auto water change running and could put a tank in my basement filled by the old saltwater. If I can find room I may pull the trigger shortly.


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Is there any reason not to do this (aside from cost)?

I'm considering a two-stage step down AWC from my display to a coral QT to a Fish QT to Drain.

Thanks for reviving this. It's an elegant solution. Lots of variation potential as well. It fills my mind with possibilities. I could see it done with gravity with only a couple of inches of step-down to keep it simple. I could see a version with multiple quarantine tanks, for different sized fish and different numbers of fish, so say a harem could be QTed in one tank.

It would very interesting to hear ideas for different variations on this. How would YOU do it?