View Full Version : Carbon block filters

10/18/2010, 02:21 PM
I'm asking this here because I've seen you guys answer questions on the board, and I get the feeling you know what you're talking about. I have a no name RO/DI unit that seems to be eating carbon block filters. I have a 1 micron pre filter, then a .5 micron filter, then the carbon block. In no time, the carbon block gets clogged and cuts production down to nothing. What could cause them to go bad after making less than 200 gallons of pure water?

Buckeye Hydro
10/19/2010, 07:14 AM
Hi Larry. Just so I understand what you have, is it:
1 mic sediment filter
0.5 mic sediment filter
?? mic carbon block?

As all these filters come before the membrane, they are all "prefilters."

10/19/2010, 12:22 PM
What I dubbed above as a "prefilter" is an add on before the unit. It's a 1 mic sediment filter then the .5 mic sediment filter in stage one of the unit, then the carbon block in stage two, which I believe is .5 mic. It could possibly be 1 mic, but more likely the .5.

Buckeye Hydro
10/19/2010, 02:27 PM
nothing that you've told me gives me any reason to think your carbon block would clog quickly. Might want to recheck the pore sizes on all those filters.


10/19/2010, 03:10 PM
Do you think a higher pressure could be the solution? The gauge reads almost 50 lbs with all new filters. By the time the unit produces about 150 gallons of pure water (750-800 gallons through the unit), I have almost zero on the pressure gauge, and production is slowed to a dribble.
The first prefilter is beginning to look a bit rust colored, but nothing past that is "dirty" by appearance.
If I remove the carbon block, pressure shoots back up to 50 PSI, and production is good again.
I thought the block was a defect, but it happened to three of them now. Two were from one source/mfgr and One was from another.

Buckeye Hydro
10/19/2010, 06:32 PM
Hmm. Did you verify the pore size on those two first filters? There is a vendor out there who advises people go with a 10 mic sed, then 5 mic carbon, and then 0.5 mic carbon. That's what I'm wondering if you have.


10/20/2010, 12:58 AM
I have no way to verify the pore size, but I'm pretty certain, just by looking that I have two sediment filters, then the carbon block. They are different in appearance and texture, and the carbon block has that plastic fishnet on it.
All three filters are new, they have only seen less than 1,000 gallons of water (total, waste and product). I just can't figure out how the carbon, protected by two sediment filters is clogged in that short of an amount of time. I know that the problem is in the carbon block, as if I remove it, everything flows like it should.

Buckeye Hydro
10/20/2010, 07:35 AM
Right. The only way that would happen is if the pore size on the carbon block is considerably smaller than the pore size on the two sediment filters. So for example, if you had a 10 micron sediment, followed by a 5 mic sediment, followed by a 0.5 mic carbon, the carbon block would end up functioning as a sediment filter for all sediment smaller than 5 micron, and about 10-15% of the sediment larger than 5 micron.

Do you have the wrappers from the sediment filters you installed? If not, you may want to start from scratch and make sure you install the correct sediment filters for that carbon block:
5 mic sediment -> 1 mic sediment ->0.5 mic carbon.


10/23/2010, 01:15 PM
I really don't think it's sediment, the blocked carbon filters are pristine white, and have produced so little water that I just can't imagine the issue being sediment. I don't know what it is, but I'm pretty sure it has to be something other than sediment.
I looked for carbon filters with a larger pore size, but was not able to find any that even list a pore size on them. Do you sell carbon block filter cartridges in different pore sizes?

Buckeye Hydro
10/24/2010, 06:08 PM
yes sir