r/o membrane ?

[kennethstowell]

i have a barracuda r/o d.i. unit . my ques, is how do you tell if the membrane needs to be replaced, my tank has had a hair and cyano outbreak for the last 3 weeks ,i replaced the di cart, about 2 weeks ago , but still the cyano persists, i rarely feed at all, the tds monitor (inline) reads normal. so i was wondering is the algae outbreak a result of the membrane being bad . the membrane is 1 yr. old, i also have another ques, but i'll post another topic

 

[AnotherGoldenTeapot]

What's the phosphate level in your tank?

 

[John G]

I have a different RO system, but I assume they work on the same principle. A quick test on the membrane is to perform an alkalinity test on the RO water. If the test changes color immediately on the first drop of reagent (alk=0) then your water is ok. Another thing, I forget the exact number, but the specs on mine said the membrane was good for 3-5 years or something like 10,000 gallons.

 

[cman]

I had the same question last week. The TDS meter read 0 but when I tested for phospahtes I got a reading of .1 comming out of my filter. I replaced my sediment and carbon filters on my 5 stage Mako and the water tested 0 for phosphates. I think you need to test with the TDS and a phosphate kit to get the real story.

I was told that when your TDS readings start to rise you need to replace the RO membrane.

 

[Eboman]

From what I understand (and what I do..), this is how you check it.

Unhook the line that goes INTO your DI unit (which will actually be the output from your RO unit). This is the water you want to check out. If the TDS measures 10% or more of the TDS of your normal tapwater, then replace the membrane. Remember, you cannot test the water that comes out of the complete RO/DI unit, since the DI unit will actually pull some of the waste passing through the RO part.

Here's my tip of the day for a Barracudda. If my TDS is anything but a 0...then I start looking for problems. The Barracudda is VERY good at stripping my water to nothing. Only occasionally will I ever get a reading of 1 or 2 on my TDS meter. That's usually only when I have not wiped the salt water drops off of the inside of my bucket after dumping the previous batch of makeup water in the tank.

Otherwise......I replace prefilters once every 6 months (they're relatively cheap). I replace RO and DI as needed or once every year (whichever comes first, which is usually 1 year).

Hope that helps,
Eboman