RO/DI equipment/water qaulity question

[tdmartin102]

I just have a quick question about RO/DI systems.

I re-started in this hobby about 3 years ago and bought a simple RO/DI unit that was fairly inexpensive. I have been using it with no problems and not giving much thought to it.

I test my water for rather simple things like Ph, Alk, Ca, Nitrates, Phos. To my continuing surprise it looks quite good. But even though my tests are showing good results, I am having issues with algae (cyano, hair, others) and awhile back I lost a couple of fish and have been gun shy about adding or replacing until I get a better handle on my water quality.

I never thought of my RO/DI unit as being an issue, but now I am wondering. This is a 3 stage unit. membrane, Carbon block and DI resin canister. The DI canister has the blue dye in it and I change it AND the carbon block at the same time whenever it turns completely yellow.

That's it done.

I have never tested for TDS.

My question to you is, should I look into this deeper? There are cheap TDS meters. I know most RO/DI units have multi stages such as a sediment filter and or multi stage DI, but I'm not so certain that it is all that critical.

My tank is simple. 50G with sadly only one fish, a 6 line wrasse, some soft corals of various types and a few hermit crabs. I have about 70 Lbs of live rock, a power head for flow, a air driven in-tank skimmer and no other filtration. I do nothing for Ca, Kh or Ph. I do a 10% water change weekly. I am currently building a sump with the intent of adding Kalk Wasser and a much better skimmer. I have to admit though, that I have been wondering about adding the Kalk since my ph has been sitting at 8.4 for a Loooonnnng time, and calcium and alk also mysteriously being quit good.

Any advice at all will be greatly appreciated as I really want to gain some confidence and move forward.

 

[serpentman]

Given their relative low cost, I would definitely invest in a hand held TDS meter as it will give you a good indicator as to the performance of your RO/DI unit as well as give you a baseline measurement on the quality of your source water.

A couple of suggestions in addition to this.

*If the unit is 3 yrs old, the RO membrane is likely due to be replaced which could be part of the problem.

*Don't solely rely on the color changing mechanism of the DI resin. If your source water is higher in negatively charged particle vs positive particles or vice-versa you can exhaust one type of resin (anion or cation) quicker than the other.

*Make sure you are batch producing your RO/DI water as opposed to continuous production. RO membranes need to run for a length of time to build sufficient pressure in order to work. If they are constantly on/off, this will result in low pressure across the membrane which ultimately ends up in TDS "creep" .

 

[tdmartin102]

Thanks,

Sounds like good advice to me. I'll pick up one of those testers, at the very least it should give me peace of mind.

I was thinking the membrane might be due. I am getting a lot more waste water flow than when it was new. Also, I don't have any top-off system so I always use the system to and do 8 gal batches (5 gal for my water change, and 3 gallons for makeup through the week) but I did not know that doing constant on/off was not such a good thing. Good to know.

Thanks!!

p.s. I saw your user image, and I just have to say that ALL of my coral came from the last C-Sea frag swap of a couple years ago, and some of them are growing like weeds. (I love that frag swap!)

 

[Buckeye Hydro]

You'll likely want to add a sediment filter, and a pressure gauge as well.

When you get your TDS meter, if you'll tell us the tds of your tap water, RO water, and DI water we can help you further.

Russ

 

[kevinohio]

I got mine from Buckeye Field supply, great buy. I got the premium with ro/di and the pressure gage. Never go wrong with a good ro/di unit.