Slow RO/DI

[BigFishy]

I just got my RO/DI unit and I got it all hooked up. The unit is meant to do 150 GPD.

The outflow for the good water is slow, but the outflow for the bad water is pretty fast. Just checking that I've got this right

 

[slm32123]

do you have a membrane flush switch? if you do try turning it to figure out which way is off

 

[BL1]

The bad water will flow more because it's usually 4 gallons of bad water form every gallon of good. It's going to seem seem slow but optimally a 150 gpd unit will only produce about 6.25 gallons per hour.

 

[treadwater]

also if you do not have a pump on the ro/di and you supply water pressure is low, your output will also be slowed by the lack of pressure. if i remember correctly an operating pressure around 50 to 55 is favorable for most units.

someone will correct me pressure if im wrong :)

 

[BL1]

it might depend on the unit I've got a filter direct RO/DI and they recommend 40-80 psi operating pressure.

 

[Brian_G]

i got an rodi from the filter guys and I get about 1 gallon of waste to every 2 gallons of good.

I have the booster pump set at 98 psi and I think thats what makes the output so great.
so i suggest a booster.

 

[Cathic]

Brian I havnt heard of a RO/DI putting out more good than bad, link me the unit please?

 

[BL1]

I would be careful setting the output pressure that high, the systems I've seen have all said that an input higher then 80psi can blow out the membrane.

 

[BigFishy]

I have the RD150 from filter direct and the PSI should be between 40-80. I don't have a pump but the PSI is a little over 50.

I let it purge for an hour and now i'm using it to fill my tank. I see lots of water changes in my near future

 

[bjohanson1234]

I have read that cold water takes longer to go through an RO unit. Maybe the water is really cold.

 

[BigFishy]

The water is pretty cold, but it says not to put hot water in. Warmish water would be good, but that'll require additional plumbing

 

[Zissou]

Yeah I hear warm/hot water as more metals in it; cold water only.

 

[slm32123]

my rodi papers from BRS said to use only cold water, not even warm water. I was watching a youtube video, and the guy was changing his filters and said something about a little "restrictor plate" that he forgot to put back in, and when he put it back in, it significantly cut back the waste. by about 70%

 

[wontonflip]

I have read that cold water takes longer to go through an RO unit. Maybe the water is really cold.

I'm pretty sure this is true. I notice in the winter months, my water flow is slow, while in the summer, it fills up a big trashbin really fast (had a couple of small floods from me not remembering in time that I was filling it up LOL )

 

[reeffreak]

Yep,I get clean water twice as fast in the summer months then I do in the winter.

 

[tankedchemist]

and that is an excellent example of how density of a material increases as temperature decreases. :mrgreen: