AIO Katalox Filter impact on water quality

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R

RookWDW

Well-known member
May 20, 2021
113
Ohio
Help.

I have an inground pool and a MasterSpa hot tub. I've never had any issues with keeping good water in my hot tub, until recently. My hot tub water is super cloudy, like milk white cloudy. I tried to increase the FC level for a while thinking it was some algae bloom. I tried to reduce the Alk/PH down. I have now changed the water and started over three times, and it turns cloudy in a day.

My main question is that a few months ago we had installed an WaterPro AIO (air injection oxidizing) filter system, using Katalox media as a whole house filter. We have well water and had some (but not crazy) iron in our water. We used to have a BigBlue carbon filter but it cut our water pressure down quite a bit. We also have a water softener but it is installed after the outside water spigot. I had the AIO setup installed before the outdoor spigot so I could, theoretically, have iron free water to fill the pool / hot tub.

This isn't the brand, but this is similar to what we got: AIO - Air Injection Oxidizing System | EarthSmarte Water.
The media: Katalox Light Iron Removal Media

I was told and believed this AIO would not add any chemicals to our water but would only reduce the iron/copper levels. Does anyone know anything about These? Could it be creating some issue? When I draw water from a house faucet, it sometimes is white, but quickly clears. I'm told it is just hyper-oxygenated from the AIO and is just oxygen and is not any chemicals.

Here is my tub setup:

7 person MasterSpa - roughly 350 gallons.
Just filled it yesterday following a cleaning using a scum/line cleaner
Rinsed with fresh water
Filled
Added a few oz of Metal Magic just in case there is any left over Iron
Waited an hour and added a few Tbls of granular sodium dichlor - SpaGuard Shock at around 8pm yesterday
FC around 3 (test strip)
Alk around 220 (test kit)
pH around 7.8 (meter)
Th around 250-280 (test strip)

Water was crystal clear. Went to bed, woke up to check the water and the temp, and it is white.
FC 0
Alk around 240 (strip)
pH around 8.3 (meter)

I added a few Tbls of chlorine and a little pH down (sodium bisulfate) just now.

So, again my main question is could this AIO / Katalox system being impacting anything? I want to try and eliminate that issue first as I never had this issue until I got the this new AIO setup.
 
Short answer - NO.

You are simply injecting air into the water source and the oxygen in the air acts as the oxidizer. The Katalox media simply makes the iron go from a soluble form to an insoluble form (rust). The filter media holds the precipitated iron like how a sand filter collects particulates. Then, when the filter goes through a backwash cycle, all that precipitated iron is flushed away.

Injecting air into the water line causes a lot of gas (oxygen, nitrogen, carbon dioxide) to get dissolved into the water at high pressure. Then, when the water comes out of a faucet, the pressure decreases and, like opening a can of soda, all that gas bubbles out to escape. None of that should have much impact on your water chemistry aside from causing the pH to be high when the natural aeration happens.

A word of advice - stop using sodium bisulfate (dry acid) to reduce pH. It lowers pH but it also leaves sulfates in the water which are not good for metal corrosion. You reduce the useful life of your heater by using dry acid. Muriatic acid is a better option and, since you are using it in a low volume tub, you can buy the low percentage 14.5% stuff that doesn't fume. Also, get a reliable test kit for doing water testing; test strips are worthless and inaccurate.
 
Thanks. I have purchased and use muriatic acid for the salt water pool. I thought the dry stuff was okay for the hot tub, but I just ran out so I'll just use MA from now on. I do have the TFP test kit and use that mostly. But, for a quick FC check on the hot tub I use the strips. I always use the ph meter for ph on the tub or pool.

Ruling out the AIO adding any chemicals, what other options would be causing milky white water in a hot tub the morning after filing? Could the high alk and ph be impacting it? I was wondering if I should fill half with post-softened water to balance out the alk and ph.
 
What line cleaner did you use? (We recommend Ahhsome here)

Please test your fill water and tub water for pH/TA/CH using your test kit. The hardness and alkalinity test on strips is not trustworthy.

Are your tub jets running in the mornings when you notice the cloudiness?

Does your tub have an ozonator installed?
 
I'll check the CH.

Tub water running around 7.8-8.0 ph and 220 alk. I've been working to lower that as I type using MA and need to retest the alk.

Source water was around 7.8 ph and 240 alk.

Water was cloudy this morning when I opened it. No jets running. It's not the typical where it turns a bit cloudy and then clears when the jets shut off. It's been coudy / white all day today. And it was cloudy for about a week while I tried to fix it, then just drained it and started over yesterday afternoon.

No ozonator.

Used "Jet Line Cleaner" from Litehouse pools this time. last several times I used Awesome, but I ran out. NOTE: this is the third refill in an attempt to get ride of milky water, the first time I used awesome, this time I used the Jet Line Cleaner.

I also did soak and rinse the filter.
 
Retested the tub water using the TFP kit.

Alk around 110-120
ph 8.0 (using meter - I'm going to recalibrate to check though) I've been running the jets to offset the drops form the MA additions.
FC around 5.0
CH between 225 and 250 (blue vs very blue color)

Still cloudy / greyish looking. vs milky white. I can see the bottom now. It's never had any brown or green color. Just white/milky/cloudy.
 
Unless you can find the ingredients for that Jet Line Cleaner, I highly suggest discontinuing it’s use. All of the products I’m finding labeled like that are using chemcials that can cause cloudiness and and foaming. Use Ahhsome only please.

Aside from high alkalinity driving up your pH, everything else seems normal. You should continue to knock down the pH until the TA gets down to 50ppm. It’s really much easier to maintain a tub when the TA low.

If the tub is left to just recirculate and the water is still, how long does it take for the cloudiness to clear up? Does it go away or does the water stay milky?
 
RookWDW said:
This morning the water is clear again. PH still way too high.

FC - 5
TA - 70-80
PH - 8.3
Click to expand...

You have to keep knocking the pH down. When you first fill a tub, especially with your high TA fill water, one of the primary balancing routines is to run the tub and do the acid/aeration process to reduce TA down below 80ppm. Most people find they need to drop the TA down to 50ppm and then add 50ppm borates to the water to keep the pH rise slow and manageable. To do the acid/aerate process, you add enough acid to drop the TA by ~ 10ppm which will cause the pH to drop down as well and then you run the jets and the tub with the cover off so that the CO2 outgassing raises the pH back up. Once the pH is back up, you knock down the TA again. You keep doing this process until the TA and pH get to where you want them. The pH will always rise in a hot tub but, when the TA is low in the 50-60 range, the pH will remain lower for longer periods of time.

Keeping the pH and TA in check also keeps the water from scaling out calcium.
 

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