Acid Washing A Pool

by Larry

Our pool is 12 years old and is in need of an acid wash. I'm trying to figure out how much muriatic acid and what type of brush (regular pool brush or a wire brush or ??) I need.

The pool is free form, approximately 20'x40, 3'-7' deep, about 28,000 gallons.

I'm not worried about safety as I am a former firefighter and will be wearing my turnouts, boots and an airpak but am concerned with our high water table, about the pool shell popping if I don't get it done relatively quickly.

Thanks for the question Larry

A normal pool acid brush can be used. You can get this from any local pool store. It's a simple wooden block with stiff nylon bristles. Be sure you get one with a pole or pole attachment.

As the pool drains you'll want to scrub it to remove any algae. It's 1 gallon acid to 1 gallon water. Use a 5 gallon plastic bucket. You can get these at Home Depot or Lowe's.

Pour the acid down the wall, from the top to bottom in a 10 foot section. Allow to sit for about 20 - 30 seconds, scrub the area with the acid brush and rinse quickly and thoroughly. Don't allow the acid to sit for longer than 30 seconds. Remember that you're literally stripping away a thin layer of plaster to expose the fresh plaster.

The bottom of the pool will probably be filled with an acid puddle and needs to be neutralized before pumping out. You can use 2 lbs of soda ash per 1 gallon of acid used. Put the soda ash in the puddle and mix with the acid brush on the pole.

The remaining acid water can be pumped out using a submersible pump.

Being the water table is high this time of year, you may be better served waiting until Spring or early Summer when the table goes down.

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.


Hope this helps.


Follow up by Larry
Date: March 8, 2013

Thanks you for the information. I was told that I could apply it with a sprayer but in your opinion, pouring it on the walls is better?

My biggest question is how much acid would I need? I have not been able to find this information anywhere on the web. The pool is approximately 20'x40', 3'-7' deep.

Follow by Robert
Date: March 8, 2013

Got it. You're wondering the amount of mixture you'll need to cover the total interior surface area, not the acid/water ratio. Is that right?

This formula will give you the approximate square feet of surface in the pool's interior. You have an irregular shaped pool. This is a ballpark estimate but it will get you pointed in the right direction.

For a free-form or kidney shaped pool the calculation is:

L x W x 1.6

20 x 40 x 1.6 = 1280 sq. ft

If you wash 10 sq. ft at a time, you'll need 128 gallons of mixture. 10 divided into 1280 = 128.

128 divided by 2 = 64. So you'll use 64 gallons of acid and 64 gallons of water.

You can spray it on but I've found that the spray sometimes bounced off and covered me. Just a few drops on my skin at a 4:1 ratio was enough to send me running to the faucet to rinse off. That's the ratio I used to clean the salt cells at the Y pool. You're dealing with a 2:1 ratio which is much more caustic.

When you hear "pour it on the walls" it doesn't mean pour the entire gallon on at once. Pour about a 1/3 - 1/2, scrub, then pour the other 1/3 - 1/2 and scrub. You need to work quickly because you only have about 20 - 30 seconds between application, scrubbing, and rinse. This is best done with a partner.

Hope I answered your question this time around.


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Well Water Supplied My Windmill

by Chuck

I would like to supply all my pool water with a windmill pumping constantly from a well that is drilled through mainly limestone. I would like to then use the constant gravity overflow from the pool to water my citrus grove, coconuts, etc. The water is fine for the purposes of the plants.

Because of the constant water change, can I get away without using chemicals for the pool? The pool would be mainly an inline temporary water storage area. Would I even need to filter the water? I am trying to build a functioning pool/agriculture system without all the chemical and power usage issues that my past pools have been plagued with.

I think my main issue would be algae control.

Any help would be sincerely appreciated.

Thanks for the question Chuck

That kind of pool sounds very interesting. It sounds like you're going for a more natural and chemical free pool. I've been associated with a couple of natural pools in Arizona, but not to the degree that you're describing.

For the algae without any kind of filtration, it's difficult to say without the numbers. I would need the water flow, readings on the water, gallons per minute (GPM) of flow, median water temperature, size of the swimming zone(s), regeneration zone(s), etc... With a high GPM and turnover of the water the chances of algae are reduced. Algae grows in stagnant water without chemicals. Flowing water reduces that.

Many natural and organic pools do have some kind of filtration system. Opposed to regular chlorine pools, the bacteria for natural pools needs to be established and everything working properly before you can actually go swimming. How much time is debatable.

Natural Swimming Pools

As it says on that page no two ponds are the same and the swimming pool chemistry is constantly changing.

Here's a link to some products that I'm familiar with:

A product that I've heard good things about is Natural Chemistry's Pool First Aid. They specialize in natural and organic pools. You can also try natural phosphate removers. Normally I discourage people in using phosphate removers, but there are exceptions to every rule.

I'd really like to know how your progress is moving along so keep in touch and hopefully I gave you some information you can use.

Best of luck


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Red Cartridge Filter

by Sherry
(Grove, Ok)

I have an above ground pool 15' with a side wall skimmer, when I changed the filter the other day the Cartridge was red colored. I use a well to fill pool and wonder if this has some thing to so with it.

Thanks for the question Sherry. Without a full set of chemical numbers it would be difficult to pin-point down why the cartridge turned red, but you can start with the metals in the water. If you haven't already, I'd encourage you to get the water tested for metals. Well water can contain higher concentration of metals than other water sources, mainly copper and iron. If the tests come back positive you'll need to use a metal sequestrant. Jack's Magic has the best line. The main ingredient you want to look for is 1-Hydroxyethylidene-1, 1- diphosphonic Acid, a.k.a HEDP. It can be found on Amazon and some pool stores. Simply follow the directions on the bottle for your situation and size pool.

And under no circumstances should you ever use a copper algaecide. If you're going to use one get a PolyQuat 60. It contains no metals and is safe for all pool surfaces.

If you feel your situation is more complex than this, I do phone and/or SKYPE consultations. It makes things go much faster and many people have found it extremely beneficial, saving them time and money in the long run. All your questions will be answered. I have nothing to sell you so you know I'm not bias. If you purchase a personal phone consult you'll get all 3 eBooks for free.

Pool Consultation

Clear Blue Pool eBook

How To Clear Up A Green Pool eBook

Swimming Pool Resources


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