RO test results

#1 Guest_Quigs_*

Group: Guests

Posted 27 October 2009 - 08:34 PM

Ive been suffering lately with a fair degree of algae in my tank, mainly Bryopsis and hair algae and no matter what I try it remains stubborn.

My RO TDS meter always says 0 however when I did a PO4 test on the output it came out at 0.03. I know its not alot but if Im chucking that amount in every night Im never really going to get my levels any lower than this, although my tank reads 0.019 due to heavy use of phoss reactor.

I only checked this as I did a water change this week and thought Id test the newly batched water which came out as 0.04 which raised my suspisions (D&D H2O)

I then changed my DI resin just in case my TDS meter was not reading correct and the results came out the same. Im running a 4 stage unit which is about 12 months old.

Are these the levels we are to expect from an RO unit?

#2 karnivor

Angelfish

Group: Members
Posts: 1,316
Joined: 18-June 08

Posted 27 October 2009 - 09:41 PM

PO4 often gets through RO units, because the molecule size is so small. Often a low TDS reading will mean that everything has been stripped out except the Phosphates. However, a DI unit should sort it out and if it isnt, then your water is leaking past the granules inside the DI due to a faulty internal seal or your Phos test is suspect.

I use a twin pod so it has a little more dwell time but TBH my water is extremely good anyway, as I have my own borehole and draw my water from 250 feet below ground.

Try putting the water in a glass with a teaspoon of di resin and see if it clears the phosphates.

Another little known fact is that many of the di resins you buy, are rejuvinated ones and not entirely new. Something worth bearing in mind the next time you buy.

#3 Guest_Quigs_*

Group: Guests

Posted 28 October 2009 - 02:53 PM

Thanks Tony - That makes sense. Didn't know about the rejuvenated resins (I suppose you know where to get the pure form from!). I'll try the resin in a glass tonight and let you know.

My ingoing TDS is only 72ish so I don't suffer too badly with poor water quality.

Ive also put Rowaphos recirculating in my top-up tank. I'll see what results I get from that tonight aswell.