saltwater 29 overflow... to guppy FW breeder tank?

[marsh]

this is a possibly ridiculous idea..

Can I re-use a SW tank with a sump as a fresh water low-light tank with guppies and use the sump below to separate the fry from the adults?

I have a dormant 29 acrylic with a stand and built-in overflow to a 15 gallon sump that was used as a SW coral and fish tank and still has sand/LR and a snail left in the water after months of being barely attended to(i top it off, one koralia running since I noticed the snail).

I ended up with it in the divorce from my ex husband, he joined my hobby but I dabble in planted tanks while he went straight for a coral LED set-up and got a steal off Craigslist with this SW set-up, I am just not focused enough to make the switch to SW what with all my many planted tanks running. One day, I am keeping the rock and supplies for the future..
I might eventually reuse the sand, assuming it can be rinsed and stored along with the LR, but I do have a hankering for a new tank to keep fancy guppies in... My first love as a child was rearing guppies and it seems like a good time to try again!

Tips or warnings?

 

[dmolavi]

Are you planning on making use of the overflow in the tank, or cutting it off via a valve of some sort? If you're going to use it, I could see the return pump creating a fairly strong pull in the sump and sucking the fry into it. I'd suggest the overflow be stopped in some way.

If they are physically separated, I don't see any reason why the sump can't be used as a rearing tank.

Overall, get all the SW stuff out (live sand, rock, etc) and clean any salt creep from the tank, rim, etc. If you think you might get into SW soon, you can keep it all in a big tupperware container w/ a heater and a powerhead. Otherwise, let the rocks dry out. You will have to cure them when you decide to reuse them.

The only way to keep the sand live is to keep it wet, if it dries, it dies. That being said, it could still be re-used later on, it just won't be live to start.