Optimum RODI Filter Sizes

[BradVol]

Let me find an old link. @flyfisher2 uses Salifert I believe. If your water is treated with chloramines you'll want something to check those.

I inserted the link again. The site was stripping it out thinking it was a media file.

I was under the impression that chloramines is just the difference in Free and Total Chlorine. And I'm aiming for none of both so if any Total Chlorine shows up I need to make a change.

 

[Woodyman]

Let me find an old link. @flyfisher2 uses Salifert I believe. If your water is treated with chloramines you'll want something to check those.

HF Scientific 9941 Total Chlorine Micro Check Test Strips, 0-1 and 1-10 ppm Range
These will check chlorine/chloramines, are accurate in my experience. Once I start registering chlorine I use a Hanna meter to verify.

You'll also want to check your water post carbon blocks but prior to membrane, as the chlorine is what will damage your membrane.

 

[Woodyman]

I inserted the link again. The site was stripping it out thinking it was a media file.

I was under the impression that chloramines is just the difference in Free and Total Chlorine. And I'm aiming for none of both so if any Total Chlorine shows up I need to make a change.

Nope, chloramine is basically chlorine+ammonia in simple terms.

 

[Opus]

Holy crap. What is your incoming TDS?

I'm going on 8+ months with my current set of filters and haven't noticed any pressure drop or TDS coming through yet.... I'm on my original set of filters from when I installed my RO/DI at the beginning of august. I started off with a 4 stage, but added 5th stage a few months ago, adding a second carbon block. the other filters are still the original ones.

Is a pressure drop the only way to tell when a sediment filter needs changing? Mine has started to discolor a tiny bit, but other than that, seems fine still.. no pressure drop though, so I'm assuming it isn't clogged. I also bought a chlorine test strip kit for testing my carbon blocks. Those are still fine too.

My incoming water has a TDS of 75 in winter months and 100 in summer months.

When I bought my RO/DI from Marine Depot during their closeout sale, I got their 4 stage for $80 and it came with a full set of extra filters too. I also stocked up on a few other filters when there were sales, so now I have a bunch of extra filters on my shelf, but my unit doesn't seem to be burning through them as quick as I had anticipated....

Your prefilters have nothing to do with tds. They are there to protect the membrane. Your prefilter takes out undissolved particles, not dissolved solids. I'm going on probably 3 years for my prefilter, but I have the .3 micron pleated filter from spectrapure which is supposed to last a lot longer than the cheap priced prefilters that most people use.

 

[flyfisher2]

Let me find an old link. @flyfisher2 uses Salifert I believe. If your water is treated with chloramines you'll want something to check those.

 

[Malcontent]

Nope, chloramine is basically chlorine+ammonia in simple terms.

You need the total chlorine test if you have chloramines:

Hach Support Online

Your partner in Water Quality - Find expert answers and outstanding support you can depend on

support.hach.com

The free chlorine test won't detect chloramines.

 

[Woodyman]

You need the total chlorine test if you have chloramines:

Hach Support Online

Your partner in Water Quality - Find expert answers and outstanding support you can depend on

support.hach.com

The free chlorine test won't detect chloramines.

The strips I linked check both. The link title looks misleading, but they do check both. They are not meant to be highly accurate but they work.

HACH is on my bad side currently... I've been waiting months for them to come validate several thousands worth of equipment..... But they make good products that are reliable, just wish they would get all my pieces and parts together.

 

[Woodyman]

The strips I linked check both. The link title looks misleading, but they do check both. They are not meant to be highly accurate but they work.

HACH is on my bad side currently... I've been waiting months for them to come validate several thousands worth of equipment..... But they make good products that are reliable, just wish they would get all my pieces and parts together.

I use the strips to ballpark, and as needed verify with one of these.

Free and Total Chlorine Portable Photometer - HI96711

The HI96711 portable photometer for free and total chlorine measurement using an adaptation of the USEPA method 330.5 and Standard Method 4500-Cl G.

www.hannainst.com

I have access to it so I use it. Otherwise I'd probably pickup the $50 Hanna hand held meter from BRS or the Salifert.

 

[Opus]

I wasn't sure whether to put this in hardware or chemistry but I think it's more related here. I need to replace my RODI filters. I have a 10 micron sediment, 5 micron carbon block, and 1 micron carbon block in a 5 stage RO/DI setup. But I see some reefing places sell replacement kits where all 3 filters are 1 micron. What would the better option be?

My tap water is 65 in TDS. The water is sourced from a combo of several wells and a river. I'm waiting to hear back whether they use chlorine or chloramines and would probably spend the extra $9 to get the carbon blocks with the catalyst if they say there may be chloramines in the water. I know Randy said most setups will remove low amounts of chloramine, but I've been struggling with hair algae and if there's a chance it could help I'm willing to try.

I've also not replaced my RO membrane in 2 years. I'm still getting 0 TDS in my water and the production rate is fine. Is there any other reason I should replace it now?

I could see you getting 10 years out of your membrane at that source tds. I've known people with 500+ tds get 5+ years out of a membrane. Just make sure chlorine doesn't get to it and you are golden.

 

[Randy Holmes-Farley Verified Community Expert]

How do you tell when the carbon blocks are done?

Mine clogged before they went bad.

 

[BradVol]

Mine clogged before they went bad.

What issues would my tank exhibit if chloramines were getting in there?

 

[Woodyman]

What issues would my tank exhibit if chloramines were getting in there?

Chloramine is going to degrade to Ammonia, so it would be like dosing ammonia, which as it's processed is going to be converted to nitrates down the line.

If the chloramines are directly added prior to degrading on their own they are going to oxidize within the tank and again degrade into ammonia.

 

[Woodyman]

Chloramine is going to degrade to Ammonia, so it would be like dosing ammonia, which as it's processed is going to be converted to nitrates down the line.

If the chloramines are directly added prior to degrading on their own they are going to oxidize within the tank and again degrade into ammonia.

@Randy Holmes-Farley can give you more of the chemistry specifics. I'm a biologist/physiologist.

 

[BradVol]

@Randy Holmes-Farley can give you more of the chemistry specifics. I'm a biologist/physiologist.

I've fought hair algae for a long time. My carbon filters are old. My tank took forever to stabilize. I'm just curious if this could cause some of my issues.

 

[Randy Holmes-Farley Verified Community Expert]

One big concern is damage to the ro membrane from chlorine and chloramine.

As to the tank, for top off water delivered by ato, there might not be any detectable issue from chlorine or chloramine since it will be very dilute and maybe no different than running ozone into a skimmer without GAC on the effluent. Water changes would be different, adding massively more new water at once.

 

[Randy Holmes-Farley Verified Community Expert]

I've fought hair algae for a long time. My carbon filters are old. My tank took forever to stabilize. I'm just curious if this could cause some of my issues.

Algae? I don’t see how,

 

[BradVol]

I'm showing about 0.5ppm Total Chlorine in the ATO water, all of which must be chloramines since it's water that has sat for several days at this point. I'm not sure if that's enough to cause any issues or not in the tank, but it's dosing about 3/4 gallon per day of that into the tank and the tank is about 38 gallons of water total.

I got all new filters and am going to see how it goes after that is setup. Maybe it will help things slightly?