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.
Here's a photo of the frag/QT tank:
Here's the back of the display tank and the frag/QT on the right:
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?