Help with RO/DI, TDS slowly creeping up.

I just bought and installed new filters, RO membrane, and DI from bulk reef supply. I have their 5 stage plus unit. I put everything together and let it run for a while to rinse everything. I got a 0 tds reading. Started to fill my new 65. After about 50 gallons my tds was now at 2. I am now at what I guess to be 100 gallons through the new filters and tds is reading 4. I'm kinda stumped. I've heard of the tds creep, but I always run at least 10 gallons through at a time and it just seems way too soon to be showing tds already? Hopefully someone can help me. Do I need new filters?

Thank you in advance,

Jake

EDIT: I'm not 100% but I believe my tds is about 45-50 entering the di, which seems awful high to me? Could this be the problem and what can I do about it?

 

What are your tap water and RO only TDS readings?
You need three TDS readings in order to troubleshoot a RO/DI system along with a few other pieces of information.
What are your water temperature and water pressure readings? What is your exact waste ratio, not what they told you or what you think it is but the actual measured waste ratio using a measuring cup and watch or clock?

Have you ever run hot or warmed water through the RO/DI? When you installed the new filters did you take the time to disinfect the system? Did you flush each filter individually before adding the next one in line so you did not contaminate the downstream filters and shorten the membrane and DI life?

 

Thanks missionsix, I should have mentioned I am using the built in dual tds meter. I know A handheld one is better but I always forget to order one when I ordering online, so I don't have one right now lol.

 

I don't have a sepearate tds meter at this time to read just the tap water but I did disinfect the system and I rinsed the filters separately before install. I know pressure is high, just shy of 90 psi. I'll check temp and watse ratio right now and get back to you. I haven't run any warm or hot water through the membrane.

Thank you, I think I got all your questions, I'll be right back with the rest of the answers!

 

AZ the temp of my incoming cold water is 76 degrees, and I think I have found something wrong, when I checked the waste ratio in one minute I got just over 500 mls of waste and just ever so slightly less purified water. So basically a 1:1 ratio. What could cause this?

 

Let me take this opportunity to thank azdesertrat for helping me out...actually, trouble shooting and finding and providing a solution,Thank you...
and to coylee_17... ..you will soon be in the land of wonderful water. 8)
not taking away from any of the words of wisdom from my other esteemed reeferz, but a water dude is a water dude...thanx rat ;D

 

Thats why I hate fixed flow restrictors, they are junk. Its possible your RO membrane is fouled and shot already since it is not being flushed at the required 4:1 ratio.

How is your waste line plumbed, you don't have any valves or restrictions in it do you?

You can test your tap water with what you have. Temporarily take the TDS meter OUT tee with the OUT probe installed, along with the short piece of 1/4" tubing then install the tee and short piece of tubing where the tap water enters the sediment filter housing so it registers the tap water. You can stick your treated water out line back in to the DI filter temporarily at this point.

Now what do you have for tap water TDS, RO only TDS which should be the IN probe on the TDS meter and the final or RO/DI TDS?

You say you "rinsed the filters the filters seperately before install". Does that mean you installed only the sediment filter in its disinfected housing then ran water out the carbon block housing exit to waste, then installed the carbon block, ran it to waste then connected the 1/4" line back to the membrabne housing? Then you installed the new RO membrane and flushed 3 to 5 gallons to waste before installing the new DI filter and running a gallon or so through it? Or does that mean you rinsed them under a faycet and installed them? Kind of unclear.

 

Waste water goes directly down the drain, no valves just a couple feet of line from the unit to the drain. I rinsed each filter in the sink under the tap (not just a quick rinse, but took my time to rinse well) before I put them in the canisters. Was that a bad idea? I'll have to switch around the TDS meter this afternoon, I'm just getting ready for work.

 

The filters need to be rinsed in the housings to draw the antimicrobials, glues, binders and carbon dust out.