plumbing plan change

[jks1]

Alrighty- the tank was delivered monday and is filling now. An incredibly slow process. I finished the plumbing for the closed loops yeterday and have to admit I am a little disappointed in the amount of flow Im getting through the closed loops- here's some pics, question to follow..

[jks1]

There are three inlets in the center of the tank, 4 outlet on the bottom and 4 outlets on the top. What you see here are the top set of outlets, but both sets produce about the same flow rates. Both sets are driven by MAG24 pumps. Here's a better shot of the flow:

[jks1]

All piping in the CL is 1". I think I am moving a fair amount of water (should be 4800 gph minus elbows, but have little pressure. The pictures above are with the outlets reduced from 1" bulkheads to 3/4" nozzles. The nozzles will be replaced with cleaner looking fittings but just wanted to get an idea of the pressure gain with reducing the diameter of the output, it wasnt as much as I hoped.

On to the ? I still have to plumb the returns. There are 2 returns which will also be 1" pipe. Both are fed from a third MAG24 in the sump. Right now the tank is drilled with the outlets in the top, so the piping would go up and over the back wall. I really dont like this set-up too much.

What I was thinking was to cut and cap off the pipes leading to the two outside top outlets. Remove and replace the bulkheads in the outside two holes, and plumb the return lines into these with check valves installed to prevent siphon if power goes out. That would allow 1 MAG24 in the CL to feed just 2 one inch outlets in the center of the top row. The MAG24 in the sump would then feed only the outside two outlets in the top row. Basically doubling the pump strength to each outlet. Here is a referrence pic.

In a closed loop is it better to have water volume or water pressure? Would I be better off keeping what Ive got and plumbing the returns into the top or switching to plan B?

By the way the top set in this pic are returns, the row of three in the middle are inlets to the CL, and the bottom 4 are also outlets.

[EdgeKrusher]

Very clean plumbing job! I'm not sure why you arent' gettnig the pressure you need. but it looks good!

[BigReepher]

I dunno but I could be way off base here. But I think the bottle neck is the 3 inlets feeding the pumps. Seems like you're sucking water rather than pushing it, therefore aren't getting the pressure you should. I would either try plan B or re-plumb to include more water inlets. If nothing else this is a bump.

[jks1]

Thanks EK, BR- I thought about , but there isnt much I can do about that now. I put the holes a foot higher than the pumps hoping gravity would help me out.

The only bad thing about plumbing the returns to the top row is the distance the holes are from the surface. I would of course install a check valve to prevent siphon in case the power goes out, but I have about zero faith in check valves and that would be a lot of water if it failed

What to do, what to do

[EdgeKrusher]

get bigger pumps.

[jks1]

bigger than 2400 gph with near zero head?? Hmm....

[EdgeKrusher]

Can you block off one of the inlets?

[addict]

Like we talked about in chat, I think it's your inlets... plus the fact that you're running two pumps off the same set of inlets, so they're creating a 'neutral' pressure zone inside the pipe as they pull against one another.

Your best bet would probably be to drill an extra inlet hole, and plumb two inlets to each Mag24.

What you'll probably have to do, is run 1.5" plumbing to each Mag24 on the inlet side, then use 1.5"-to-1" reduction bushings where the plumbing connects to the 1" bulkheads, and where it enters the pump.

That's about all I can offer... I hate to have to tell you that you may need to redo your awesome plumbing job...

Otherwise it looks like things are coming right along... I hear ya on how long it takes to fill the tank with RO/DI... it took me 5 days to get 5 30g trashcans full with an 85gpd RO/DI unit.