why not to hook up RO/DI to sump

[Big_Pun]

great article Marc always writes great stuff. I've learned alot from melevsreef and his new site reefaddicts

http://www.melevsreef.com/rodi_recipe_for_disaster.html

[rrasco]

My original plan was to have my RODI keep my topoff reservoir full which would then ATO to the sump. However, I decided to use an additional container for the reservoir which limits the RODI water that can be automatically pumped into the sump as topoff. This leaves me with the manual step of opening a valve to keep the ATO reservoir full, which is super easy and let's me sleep at night.

[Big_Pun]

it also runs down your membrane and DI life

[rrasco]

Yes. Helps if you flush it regularly.

[allan]

not to mention that the little stopper thing that prevents waste water from running while not producing RODI give up fairly easy.

I have mine connected to the sump... but I only turn it on for about an hour every other day or so. If I had the room I'd do a remote container as well.

[Bill S]

Membranes leak - so the first bit out of the unit is not of low TDS. Quick cycling does not make for good water quality.

[Mr Cob]

yeah, I'm totally a fan of not automating everything. I use an Auto top-off as he suggested but only keep a reservoir no larger than what my system can handle in the event that the auto top-off pump dumps all the water in the sump, the system can handle the extra water and not be impacted via salinity.

I never liked the idea of feeding the ro/di directly to the sump or even to the top-off container.

My only real worry on my system right now is the fact that I drain my skimmer's collection cup to an external container...if my skimmer goes out of whack and skims wet I could drain water from my system via that little tube.

[rrasco]

I've really been trying to devise a way that I don't have to keep my filter on since I know the short cycles are not best for the membrane, but as it sits now I open a valve and put a gallon or two in the ATO reservoir, which lowers the RODI container level and activates the float switch opening the solenoid to refill the RODI container. I can turn off my RODI supply and unplug the solenoid (or it would stay open when the water level drops). The problem this creates is if I need to refill the RODI container that leaves the solenoid energized for a longer period of time, which is not ideal for them either. I really don't know what options I have for modifying my system so I get the best of both worlds. It really is nice having a RODI on hand at all times, especially when it refills automagically as I use it.

Someone also got me thinking when they mentioned the ASOV go out fairly easy.

[Big_Pun]

rrasco I would just manually run the reservoir and only when it's empty. no reason to have the RO/DI unit come on automatically. when you see it low just start running it and let the auto shut off system /float valve shut it off . it's better to run it 4 hours than on off. I have two 55g linked and when they run dry i go turn on my filter and water grass with waste, then just use the up water till I need to make more water.