ro/di filter question

[hobbes1]

I replaced my ro/di filters a little over a month ago. When I replaced them I was reading 0 TDS coming out. I have what I would consider very high readings coming in. They tend to hover around 400. I have done several water changes within this month because I am trying to get my tank in shape. During this past month it has risen to 9 TDS. Is this abnormal?

From doing searches in the forums, it seems like people are averaging 6 months and they are still getting readings of 1 coming out of their DI. I have only recently started monitoring TDS so I don't know if this has been issues all the years before this.

 

[jdezek]

What brand RO/DI system do you have? I'm having similar issues with my coralife 50gpd system. I just replaced my filters and only got about 120 gals and readings jumped to 40. Replaced DI resin and it went back to 0 after 80 gals its back up to 60. People in my club say they heard others having issues with the coralife systems. I'm not sure what my readings are straight out of the Faucit but after the first filter its only reading 90.

 

[azjohnny]

Any reading over 1ppm after DI is unacceptable.

What is your reading after the RO membrane? If it is over 20 I would replace the membrane (95% rejection rate with 400ppm feed water)

 

[hobbes1]

I am actually not sure what brand the RO/DI is. I have had it for years. I am just recently getting back into my tank. When was in it before I did not realize the importance of testing your TDS and didn't realize how bad off it was.

The reading after my RO membrane is close to 60. So should I look into replacing the membrane? Also, I purchased 1 micron for both the sediment and carbon. Should I go with a lower number?

 

[azjohnny]

Time to replace the membrane and with the sediment and carbon filter go as small as possible, they serve to protect the membrane.

I run these in my system

sediment- .2 micron
carbon - .5 micron

IMO go with Spectrapure products

http://www.spectrapure.com/

 

[hobbes1]

Thank you for the help.

 

[Breadman03]

Time to replace the membrane and with the sediment and carbon filter go as small as possible, they serve to protect the membrane.

I run these in my system

sediment- .2 micron
carbon - .5 micron

IMO go with Spectrapure products

http://www.spectrapure.com/

My water has a lot of sediment, so I run 15 micron, then .2 micron sediment, then a 5 micron carbon block, then a Spectrapure 98% RO, then my DI. Spectrapure announced 99% rejection membranes, which will result in much longer DI lifespan.

My original RO membrane was only about 95% rejection and gave me about 80 gallons before the DI was exhausted. The 98% membrane gave me over 400 before I changed my DI due to a GHA outbreak and wanting to eliminate my water as a phosphate source.

The membrane is the workhorse of the filter system. The sediment frees and carbon block just protect the membrane, and the DI polishes what the membrane doesn't get.

 

[hobbes1]

My water has a lot of sediment, so I run 15 micron, then .2 micron sediment, then a 5 micron carbon block, then a Spectrapure 98% RO, then my DI. Spectrapure announced 99% rejection membranes, which will result in much longer DI lifespan.

My original RO membrane was only about 95% rejection and gave me about 80 gallons before the DI was exhausted. The 98% membrane gave me over 400 before I changed my DI due to a GHA outbreak and wanting to eliminate my water as a phosphate source.

The membrane is the workhorse of the filter system. The sediment frees and carbon block just protect the membrane, and the DI polishes what the membrane doesn't get.

I was actually looking at the membrane you are talking about. Are the membranes typically a standard size like the other components are? I have never replaced the membrane before.

 

[shifty51008]

don't forget, if you change membrane GPD you must change the flow restictor to the size membrane your putting it.

 

[Breadman03]

I was actually looking at the membrane you are talking about. Are the membranes typically a standard size like the other components are? I have never replaced the membrane before.

don't forget, if you change membrane GPD you must change the flow restictor to the size membrane your putting it.

I don't know if they are all the same size, but at least most are. For example, I have a BRS filter housing, but am using a Spectrapure branded membrane made by Dow.

 

[shifty51008]

yes the housing will fit other sizes, I am talking about if say you have a 60gpd membrane and wanna switch to a 75gpd membrane then you also have to change the flow restrictor to match the 75gpd membrane

 

[hobbes1]

I did not know that about the flow resistor. Glad I did not order it yet. I took the old one apart yesterday and it is a "Filmtech". When I get home I will check the GPD. Hopefully it matches up. Is it a big deal to change the flow resistor?

 

[azjohnny]

I did not know that about the flow resistor. Glad I did not order it yet. I took the old one apart yesterday and it is a "Filmtech". When I get home I will check the GPD. Hopefully it matches up. Is it a big deal to change the flow resistor?

Yes

it controls the back pressure of the waste water tube, you want about a 4/1 ratio of waste to good water, this helps to keep the membrane clean

 

[BubbaBoBobBrain]

Adding a flush kit to the membrane will also greatly extend the life of the membrane. Flush for a few minutes before making rodi water and then flush again after making the water and you should get much longer life from the membrane.

 

[Breadman03]

I did not know that about the flow resistor. Glad I did not order it yet. I took the old one apart yesterday and it is a "Filmtech". When I get home I will check the GPD. Hopefully it matches up. Is it a big deal to change the flow resistor?

It is a big deal as to matching the proper flow rate, but not a big deal at all when it comes to effort.

 

[hobbes1]

I am unfamiliar with the flush kit. I see that on the Spectrapure website that they sell the ro/di units with auto and manual flush kits. So, this is something that I can add on to the unit that I already have?

I found a video on youtube about how to change the flow control. Looks pretty easy. I went ahead and bought the Spectrapure 99% rejection 90 GPD membrane and a flow control for it. Hopefully this will improve things. Going through filters in a month is no good.