View Full Version : Problem with RO unit

04/28/2010, 05:34 AM
I was losing water pessure in RO unit. Carbon unit was the problem, replaced it and everything was fine. Now I made about 500 gallons of water and I am losing pressure again. I also have two DI units connected to filtr, replaced at the same time as carbon and they read 25 TDS. Have used this filter unit for years with no problems until now. Can you help. What can I do.
Thanks Ed

Buckeye Hydro
04/28/2010, 06:30 AM
Hi Ed - be happy to help you. We'll need some information -

What brand is your RODI?

How many stages? And what are the various stages?
What is the micron pore size of the sediment filter and carbon filter(s)?

Are you on well water or city water?

What is your water pressure?


04/28/2010, 01:28 PM
Thanks for getting back to me. It is Kent RO unit
first stage sediment 10 micron
second stage carbon BFS-2
third and fourth stage DI resin
RO membrain 75 gallon per day

water is at 50 PSI

Thanks again for your help

Buckeye Hydro
04/28/2010, 05:11 PM
Ed - Looks like your sediment filter and carbon block are mis-matched, and because they are, the carbon block is acting like a sediment filter for everything smaller than 10 microns - and you've seen the results.

In general, the pore size on the carbon block should be about the same size, or larger than the pore size on the sediment filter.

So go with a 1 mic sediment filter matched with a 0.5 micron carbon block, or
a 5 micron sediment filter with a 5 micron carbon block.


04/29/2010, 04:16 PM
Thanks for taking the time to help. I will be placing an order at the beginning of the week.
Is this why the DI is being used up so fast?
Thanks ed

Buckeye Hydro
04/29/2010, 04:49 PM
It may be that the RO membrane is so starved for pressure that it is not operating well.

Can you give me some info?

Water pressure at the membrane?
TDS of tap water?
TDS of RO water?
TDS of DI water?


04/30/2010, 08:25 PM
Thanks for your help. The PSI gauage is int RO housing. I am going to order a inline PSI gauage to try and get a better reading on pressure before and after the filter unit. New filters and pressure boost pump if needed. Thanks again for your help.

Buckeye Hydro
05/01/2010, 03:46 AM
Ed - the pressure gauge should read after the prefilters and before the membrane. We have two pressure gauge kits here: http://www.buckeyefieldsupply.com/showproducts.asp?Category=201&Sub=109