Please comment on my RO/DI design

[morgan1965]

After reading several Reef Central threads, I've decided on a Ro/Di design which combines an AWI Typhoon with a Spectrapure Pass to Drain kit (Configuration #5) for my 550 gallon system. Here's my basic idea:

1. 25-50' of tubing in sump to warm the input water to 77 degrees
2. booster pump, if necessary
3. 10 micron sediment filter
4. 5 micron carbon filter
5. 1 micron carbon filter
6. Spectrapure Pass to Drain as a controlling unit with auto bypass remote valve, pass to drain remote valve, and pressure switch on ouput line
7. three RO membranes in series
8. product water split: one through kalk reactor to topoff (controlled by solenoid mounted in sump) and the other to a 90 gallon open storage tank for water changes (controlled by float valve)


Questions:
1. I want to be able to monitor the function of each part of the system. Where should I locate TDS meters and pressure gauges?


2. I've seen a surge tank used in the product water line for discharge pressure management. How does this work and why is it needed?

All comments welcome!

 

[BLockamon]

I assume you mean three RO membranes in parallel (able to run at the same time). If you mean in series (one after the other), I doubt you'll have enough pressure to push water through the second and their membranes.

 

[crumbletop]

1) So no DI?
2) As BLockamon says, the RO membranes in series seem odd and I don't think it would work.
3) With the amount of water you'd shuffle through, I doubt the sump would warm the input water very much.
4) I would't hook up the RO output directly as top-off -- if the solenoid sticks open, you're hosed.
5) The product water (coming out of the RO) is low pressure so I don't know why you'd need any kind of pressure relief. I suppose if there were no auto shutoff valve on the input side, then pressure could build up in the output if the output was blocked. Take that with a grain of salt though, because I have no idea why the pressure would ever build up in the output line -- I'm just guessing.
6) I don't think you really need to monitor the TDS all that often, so setting it up to monitor at multiple points would be a waste of money IMO.
7) If you're worried about cold water slowing down the RO output, why not get the eskimo instead of the typhoon? It comes with different flow restrictors that are taylored to colder water on the input side.

Jack