Some Basic RO/DI Questions

[boojumsnark25]

Well I've been thinking about getting an RO/DI system, my tank has been pretty successful on just well water, but i'm always dancing a fine line with hair algae (2 days late on a water change and my tank is overrun). So, I'd like to do an RO/DI system. My tank is in a finished room in the basement, and my sump is through the wall and in a space behind the room in the basement. Neither is anywhere close to a faucet. Across the basement is a laundry room with a cold water tap, which is the only possible place I could use. Here are my questions:

My plan was to run a hose from the cold water tap straight up, fastened across a rafter going along the basement ceiling, and over and straight down to my sump. I was going to use a 45 gallon rubbermaid trash can as a reservoir. First question, if the system comes with an auto shut off and I get a float valve, could I run my top off out of the reservoir, or is the constant starting and stopping bad for the ro/di system?

Second, and I think this is where I'm going to run into trouble, is there any pressure on the drain water from the ro/di, or is it just a gravity deal? It would have to go straight up, over to the laundry area, and back down to the drain hole over there, so it would have a lot of head pressure to battle.

One more question - this plan would require the cold water tap to be constantly in the "on" position - is this a problem?

Thanks in advance!
Greg

 

[fsn77]

I would not recommend directly connecting your RO/DI unit to a float switch and using that to top-off automatically. If the float switch fails to close, you will flood the tank with freshwater and likely lose a large amount of livestock.

The waste line from the RO membrane needs to flow freely, as in no head pressure or back pressure.

The cold water tap for our washer is where our RO/DI unit is connected, with a Y adapter, and is always on. It's never been a problem.

 

[boojumsnark25]

So I guess I'd have to have another trash can for the drain water, with a reverse float valve, and it would turn on a pump when it fills up and pump the water to the drain?

 

[mukymuk]

r is the constant starting and stopping bad for the ro/di system?

I don't think it's bad for the system mechanically, but I think it will result in less efficient filtration. However, if your water is decent to begin with, it might not be a problem.

So I guess I'd have to have another trash can for the drain water, with a reverse float valve, and it would turn on a pump when it fills up and pump the water to the drain?

I don't think so. Running it up a wall, over, and then back down creates very little back pressure compared to that imposed by the flow restrictor device itself. It's essentially just the resistance imposed by the longer length of tubing. Going up will add head pressure , but going back down will subtract head pressure. Not an issue in your scenario, IMO. I'd give it a shot.

One more question - this plan would require the cold water tap to be constantly in the "on" position - is this a problem?

Mine has been on for 15 years. No problems yet.