Free CO2 and DI depletion

Hi! Long time no post. In a nutshell, for 2 years i was skipping the di phase due to amazingly high CO2 levels in my water that ate all my resin. Well, my tank did not do so well, and over the summer it accelerated and all my SPS and most of my LPS died. And I was lazy testing my water, assuming all along that my water was at 5-6ppm. Well, I was pumping 48ppm into the tank! The RO membrane somehow had failed. After 6 years I stupidly crashed my tank, and spent the next six months not caring. The fish and inverts are fine, but my once beautiful reef is barren.

So Ive decided to fix it. Bought a brand new spectrapure 90 gpm unit, replumbed it so there is one more carbon block and a seperate DI. I purchased a booster pump. I made a degassing tower. I bought a handheld TDS meter, a ph probe and a CO2 test kit. All in all I threw over $300 into this project.

I fired it up yesterday and let it run. I tested the effluent this morning for CO2.

Free CO2 after RO = 76
Free CO2 after Degass= 7

Obviously I have achieved a stunning reduction! But I cannot find citations for normal/average/optimal, so i don't know if I have further to go or 7 is good. Does anyone know these numbers?

 

Contact Spectrapure, they have a lot of experience with this.
Why did you add an additional carbon? If this were needed they would have added it in the first place. Everything you add in front of the membrane has an effect on incoming pressure and lowers the membrane efficiency, this is why Spectraure uses only one high quality carbon capable of either 12,000 gallons or 20,000 all by itself as long as you use the equal sized or smaller sediment filter in front of it. They have 30+ years of research and development so their system are the most thought out you will find on the market.

 

I added the extra carbon before the di stage because I had an empty canister to fill. The Spectrapure unit has sediment -carbon- Ro-Di. Since I am not making di with this unit (di occurs at separate stage) I re-plumbed it to go sediment-carbon-carbon-ro. I would happily skip the extra carbon if that chamber can run empty, particularly if ir would help membrane life. Can it run empty?

 

Yes it can run empty. Did you replumb it so all three cansiters are before the RO membrane now? If so I would put it back to its stock plumbing and place a DI back in the final canister. The DI doesn't have to be remote unless you have space constraints and have your degassing set up in another location. You can always run the RO over to your degassing tower then back down through the DI on the existing bracket then an additional DI if you think you need two. Or just leave it empty and disconnect the line from the RO to the DI and run it over to your tower. I prefer using what I have and keeping things as compact as possible.

 

I might run it empty, then, if that is your recommendation.

The DI unit is remote because I am unable to make DI at the same rate as the RO due to the limitations of the pump I am using (toms aqualifter because I cant think of anything else). The DI is made at 1/3 the rate of the RO until I improve the system.

 

welcome back pdxile! good to see you posting again and sorry to hear about the crash it sounds like you have a good plan in place. I'm afraid I'm not knowledgable on your question but az sure is!

 

http://spectrapure.com/PUMPS-POWERHEADS/DIAPHRAGM-PUMPS/Replacement-Low-Flow-Booster-Pump-6800

 

The Aquatec 6800 is a good RO booster pump for up to 50 gpd membranes. It is a booster pump and not a transfer pump so would burn up without head to pump against. Aquatec does also make transfer pumps but you don't need anything that big or that fast. With DI slower is better since it is the contact time between the resin and water being treated that does the job.

 

Yikes, I am doomed to make water at 2.5 gallons per hour then. my immediate goal is to make 80 gallons of RODI. See you in a week. :-(

 

Sorry to Hijack-
Hey ADR,
ON my Gen. water Manufuring Co. model, my DI (sith a small carbon filter also) is
AFTER the membrane and storage tank, no before the membrane.
At least I think that's the way it runs.

Is this OK?