Flakes In Hot Tub Water

by Don
(Sudbury Ontario Canada)

Our new 450 gal hot tub has been in operation for 3 months. The alkalinity was originally 110 but has steadily increased to very high above 240. Recently we are starting to see flakes in the tub. The flakes only occur after the jets are turned on.

The pH is kept high at 8.4 in order for the natural enzyme chemicals in the pool to work. I was told the flakes are due to calcium deposits in the piping and that the jets wash them out when they are turned on. The filter cannot remove the flakes fast enough.

I have recently added 6oz muriatic acid to the tub and will wait 1 hr before circulating the water through the piping by running the pumps. Then I will test for acidity and alkalinity and repeat the process to reduce alkalinity if required. Will balancing alkalinity this way eliminate the flakes? What should I use to clean the piping if it is a calcium buildup problem?

Thanks for the question Don

First we need to know what you're dealing with, whether the flakes are organic or inorganic. Get about 4 - 8oz. of hot tub water. Try to scoop up some flakes and put them in the container. Put 15 - 20 drops of bleach or liquid chlorine in the container, gently mix, and allow to sit for 30 minutes.

If the flakes disappear, it's organic, which probably means white water mold. You can go here to learn how to get rid of that:

Water Mold

If the flakes stay, it's probably calcium and/or mineral. To get rid of any calcium build-up around the water line you can normally use either a pumas stone or a ceramic brush along with a muriatic acid/water solution. 4 parts water to 1 part acid. Be sure to wear goggles and rubber gloves.Also wear old clothing (long sleeve shirt and jeans) that you wouldn't mind getting stained or bleached out because of the acid.

To get rid of any possible calcium build-up in the pipes, you can add a quality Mineral Treatment, to help sequester the calcium, on a regular basis. Over a period of time, this treatment can actually slowly dissolve calcium scale deposits. I would encourage you to get an FAS-DPD K-2006 Taylor test kit. It's the best on the market.

Water Testing Kit

Being that you're using a hot tub enzyme you do want to keep the pH between 7.8 - 8.2. The Taylor kit does go up to 8.0 (very bright purple/red) but anything over that you're pretty much guessing at the pH level. Try to not go over 8.2 if you can help it. Test your tap water as well. High calcium fill water might be an issue so you may need to drain and refill your hot tub from time to time as the hardness level increases.

Try to not use any products that will increase the hardness such as calcium hypochlorite (chlorine granules). Get the alkalinity between 80 - 100ppm. 120 is fine but try to not go over too much. The link has the charts you need.

Pool Alkalinity

Getting the alkalinity in check will not help with the calcium issue. You need to try to keep the calcium down under 250ppm if you can. Hope this helps and let me know how it turns out for you


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White Water Mold In Jacuzzi

by Kristoffer
(Denmark, Bjaeverskov)

Sometimes I have white stuff in my jacuzzi, and when I rinse the filters is looks really bad in the bucket that I am cleaning it into.

Is this White water mold that I got?

I use active oxygen as a sanitizer. I have used chlorine and bromine in the past, but got a rash from them, so going back to that is not an option.

I hope you can advise me of what to do about this.

I am traveling at the moment and do not have any pictures that I can upload, I just came across your webpage by luck I guess

I hope that you will reply to my question above! :-)



Thanks for the question Kristoffer

To the best of my knowledge active oxygen is not a sanitizer to keep bulk or spa water clean. Here in America there are 4 EPA approved sanitizers - chlorine, bromine, Baquacil/biguanide/PHMB, and Nature2 with MPS (non-chlorine shock). Nobody and no product can claim to kill bacteria except those four.

Are you using a BAYROL active oxygen system? This is common in Europe. Bayrol in Europe is equivalent to Bioguard here in the U.S. The products of active oxygen, Softswim line, which is also sold in the U.S. under the Bioguard name. It's the Biguanide antimocrobial peroxide that sanitizes the water, not the oxygen. The peroxide is an oxidizer.

Bayrol is the European brand of Chemtura Corp. Some of their U.S. brands are Bioguard, Sun, Guardex, and Pooltime.

Peroxide might be good for a weekly and temporary sanitizing, but eventually you will get water mold. If you have white and/or tissue like substance floating in the water, it most likely is white water mold.

As the water mold page says, when you finally see it your hot tub is already infested with it. The only way to rid the water mold is to shock with chlorine.

Water Mold

You can also add an enzyme like SpaGuard Natural Enzyme, Natural Chemistry Spa Perfect, or Baqua Spa chemicals. These enzymes actually "eat up" the problem for a great chemical help.

Many people do a full drain and refill but don't shock the spa. There's still mold in the lines, heater, and filter. This must be taken care of or you'll repeat the process of mold all over again.

It's bad that you can't use bromine or chlorine, but unfortunately, to the best of my knowledge, there's no easy fix for white water mold other than what I've written in this post and the water mold link I provided.

If you need immediate assistance (within 24 hrs) or for emergency personal assistance, you can make a donation of your choice and I'll answer your questions by phone.

Contact Me


Hope this helps and have a great Summer.


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White Fluffy Substance On Floor Of Pool

by Gary
(Caloundra QLD )

I have a swim school and of late have been getting a fluffy like substance which is floating just on the bottom of the pool floor.

If you try and vacum it it dissipates away and seems to dissapear for a while.

Had it real bad then I used a floc and vacuumed to WASTE for weeks.

Went away and now slowly back each morning when I take the cover off.

Thanks for the question Gary

It sounds like your pool has a case of white water mold. This normally happens with hot tubs due to the high temperatures, but it can happen with pools from time to time.

Water Mold

The best thing to do is to shock your pool and follow the directions in the above link.

Swimming Pool Chlorine

Pool Shock

These links to pool chlorine and shock, along with the page to white water mold will more than likely clear up your pool.

Home pool's chlorine level should be between 1.5 - 3.5ppm.

The question says you have a swim school so I will assume it would be regarded as a semi-heavily used pool. In this case you may want to bump up your chlorine level to 4.5ppm.

This is still a very safe level and will probably take care of any mold or algae issues.

Hope this helps and have a fun and safe swimming season.


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