Been keeping track of gallons throughput of my RODI since setting it up in April '09 on an Excel spreadsheet. Other than the poly pre filters I prefer to use gallons throughput rather than months as criteria for when to change my carbon filter. The documentation for my 0.5 micron carbon block says it's "Highly effective for chlorine.... for up to 20,000 gallons at a rate of 1 GPM".

According to my calculations, I've put an estimated 12,600 gallons through my system in just under 3 years. I say estimated since I'm using not only gallons of pure water produced, but also adding 4 times the amount of pure to the total since there's an estimated 4 gallons of waste for every gallon of pure water produced. This all goes through the carbon block. The 1 to 4 ratio is an approximation & I can only guess that since I don't measure this every time I produce water. I'm a cheapskate & don't fancy the idea of changing my carbon filter after 4 months if I haven't come anywhere near the rated gallon amount the filter is supposed to be good for. When feasible, I also like to verify manufacturer's claims so that I don't knacker my RO membrane before its rated life. So a few months ago I decided to check for chlorine at the tap source as well as after my carbon block. Results follow, I feel warm & fuzzy that my carbon block is still good & can go for a few thousand gallons more.

Sorry getting a little off topic from chloramine, but there has been some info provided in posts here regarding when to change certain filters.

Two photos since it may be difficult to tell the colour difference, one made with flash & one without. Should be able to tell on the strip in left of photo chlorine is 0 whereas the one on right shows a touch of purple indicating the presence of chlorine. This of course is the one dipped into the source water & the left one is after the carbon block.

https://public.blu.livefilestore.com...62e.JPG?psid=1



https://public.blu.livefilestore.com...61e.JPG?psid=1

Mike, will your test strips also check for chloramines?
Thanks

Don't think so. It's an AquaChek pool & spa test kit. You can see on the colour chart that it tests for 'free' chlorine. I'm assuming that since chloramine is chlorine combined with ammonia, it won't provide accurate indication of the presence of chloramine. However, since a carbon filter is supposed to separate the chlorine & ammonia, it may still be useful to check for traces of chlorine after your carbon stage. AquaChek has a web site so you could probably find more info there.

Thanks Mike.
I see on their website that they also sell a strip that tests for 7 parameters.
Two of interest, free chlorine and total chlorine. I think the chloramines would be included in the total chlorine

Ya, not a bad deal these strips. As you can see the one I have also does pH & alk. Don't recall if I tried one of these strips in my tank water. Might should do that some time & compare to the liquid test kit readings. According to their site, the strips may end up being more accurate due to less prone to errors as when counting drops of reagent with the liquid kits.

If you're testing for chloramines, make sure the test kit is testing for "total chlorine" or "combined chlorine," not for "free chlorine." A test for "free chlorine" would misleadingly read zero in chloraminated water.

also by testing for amonia you can determin if there is chloramines present.

heres a good read http://reefkeeping.com/issues/2003-11/rhf/feature/

Steve

would the chlorine test kits work with salt water? Thinking maybe testing for a possible buildup of chloramine in the display.

So does this mean i have to put bubble stone in my after RO/DI water before using it? I am in NW so i guess I am using Bearspawn

I sent an email a few days ago to SpectraPure asking some questions about chloramines and filter cartridges, but haven't received a reply yet. I will send a PM to Buckeye Field Supply...I'm surprised he hasn't hopped in on this thread yet.

Thanks for posting Mike, where do you get those test strips? I've been wanting to buy chlorine test strips...maybe they have one for chloramines too.

I tested my RO/DI water for ammonia and there was no ammonia detected. I should test before the DI resin.

Total chlorine - free chlorine = chloramines (in our case anyway)

The test strips are for pool/spa. You should be able to get them any place that has pool or spa maintenance stuff. I think I might have seen the kit at Wal Merde but I got mine at a spa/hot tub business outlet. It's an AquaChek as you can see in the photo I posted. They also make kits that test for 'combined' or 'total' chlorine, but I'm not sure what that means exactly... combined with what? May or may not be ammonia. I think I read somewhere in the research that once chlorine hits the water, it starts 'combining' with some of the stuff which it's designed to kill or neutralize. This may not necessarily be ammonia, which is what it's combined with to make chloramine? Confused yet? I sure as hell am & real glad Vernon just uses chlorine.

There's already some good info on chloramines & how to best deal with them for our application on the Spectrapure FAQ site:

http://www.spectrapure.com/SYSTEM_BREAKDOWN.htm

phideltreefer already posted the link but only provided a partial quote in is post here. If you read the whole article, most of your questions should be answered.

"Our dual cartridge combination of DI-SF-CI-10 followed by DI-AR-CI-10 is an effective and more economical way to remove the ammonia"

Steve's link to reefkeeping pretty well covers it too....