Using TDS measurements

[Pikelet]

I have been concerned about recent readings taken with a TDS meter dipped into my prepared RO/DI water. I'm using a 4 stage unit. Current readings are 4ppm but I used to get 0-1ppm when I first added a DI chamber to my RO unit.

 

At what TDS level should I be looking at changing out my RO membrane and carbon filter?

[reef93]

How long you haven't changed your carbon filter? If you have flush kit, give membrane a boost.

[Pikelet]

I've had the carbon filter and RO stages for about 10 months.

[reef93]

The carbon and sediment filter usually need to change every 6mo. RO membrane usually last arond 2-3 yrs. Did you noticed your RO unit perfermence declined?

[Pikelet]

No .... I haven't noticed a slow decline. I measured it when I first got the TDS meter and DI and I was getting 0-1ppm. After about 4 months I checked it again and I was up to 4ppm. I only checked because I had an outbreak of cyano. I was just wondering whether there was a rule of thumb when it comes to changing it because many people buy a TDS meter to check the status of their RO/DI units. I have yet to find any information on an appropriate point at which it needs to be changed by using TDS readings.

[reef93]

I don't think your algae outbreak relate to 4ppm of rodi water. I used tds to indicated when I need to change filter, generally 0-5ppm I will not worry about anything. 5-10ppm, I will check my carbon and sediment filter. 10-15ppm, check the DI resin and flush your RO membrane regular. At least your carbon filter last longer than mind(only last 4mo... due to hard water). Here is the checklist for algae outbreak

nutrient excess? (phosphates should be very low)

overfeed?

overloaded?(fish,coral..)

[Dave ESPI]

check the DI it should be colorchange resins (if U have a good one) perhaps yer probe needs calibration?

[Pikelet]

Thanks for the replies, everyone. I think I'll go ahead and change out the carbon filter to see whether that improves matters. I'll keep you up-to-date with the results.

[tinyreef]

what is your lighting situation? (bulb age and color) that's often a culprit of sudden cyano outbreaks.

[Pikelet]

2 x 55W 10K PC's, 1 x NO Actinic03. Tubes are all 9-10 months old.

[Pikelet]

I finally made it to Aquatic Reef Systems today to sort out my RO/DI issues. There was a problem with the DI cartridge. The cartridge was collapsed on one side as though something had sucked out the inside - very odd. Anyway .... the end result was that the water flooded the DI unit completely and the throughput was extremely limited and inconsistent as a result. I took the opportunity while at ARS to replace my carbon/sediment filter to protect the RO membrane better. My TDS out is now down to zero again. Thanks to John and Brian at ARS for resolving the problem so promptly. Great company.