Build up at bottom of the pool - Pictures

[TFP_Addict]

My readings (T-2006)

FC - 12.5
pH - 7.4
TA - 180-200
CH - 750
CYA - 80-90

In the last week, I was having issue regarding yellow algae. I raised my FC from 4.0 to 12.5. My pH was at 8.0, now it's 7.4. Even after sweeping the pool with a brush. There are areas on the bottom of the pool that look like dirt, but isn't. I don't know what it is. Hopefully these pictures can show you what i'm talking about.

A few years ago, we removed all the water from the pool and did an acid wash. The pool looked perfect. Now there is scaling at the bottom of the pool that doesn't brush off.







Any ideas?

 

[TFP_Addict]

Another thing I want to address is CH - 750. I test the water the refills the pool, and the CH is at around 200-220.

We have a large water softener that works for the house. If I were to use pool water for gardening and then refill the pool using water from the water softener. This would help me lower these levels correct? Any downside to doing this? Seems like the cheapest alternative, and my City won't notice a huge spike in water usage.

 

[bdavis466]

Scale, and it looks like you still have algae as well.

Your TA, pH, and CH were all very high which caused the scale to build up. There is nothing wrong with each of your numbers but when you combine them together, they potentiate eachother and make for water that is oversaturated with calcium carbonate. You can attempt to drastically lower the TA and keep the pH around 7.2 in hopes to dissolve some that scale but it will be a very long and slow process. Your best chance of removal is likely another acid wash but may not be possible based off the condition of your plaster.

If you had algae and only raised the FC to 12.5 then you did not kill everything in the water. With a CYA of 80, you should be maintaining a FC level of 34 until you pass all of the SLAM criteria.

Where are you located in CA? How old is the plaster?

 

[kimkats]

Just remember the water softener can only hold/treat ?? amount of water. Once you have reached that amount you will be using "regular" water again until the softener recharges.

Run your numbers through Pool Math. Look at the CSI area towards the bottom. Share that with us and we can go from there with your "staining" or what ever it is.

 

[bdavis466]

Another thing I want to address is CH - 750. I test the water the refills the pool, and the CH is at around 200-220.

We have a large water softener that works for the house. If I were to use pool water for gardening and then refill the pool using water from the water softener. This would help me lower these levels correct? Any downside to doing this? Seems like the cheapest alternative, and my City won't notice a huge spike in water usage.

That would take forever. To lower your CH level, you would have to drain 75 % of the pool and that would get you to the 400 ppm range with your full water CH level. A residential water softener was not design to process that large of a volume of water. There are reverse osmosis companies locally that filter your water of the CH without draining the pool.

With a pH of 8 and your current numbers, your CSI is 1.12 which is double the level where scale occurs. Your CH is easily manageable (mine is higher than yours) but you can not have high calcium levels with very high TA and not expect scale to form.

 

[TFP_Addict]

Just remember the water softener can only hold/treat ?? amount of water. Once you have reached that amount you will be using "regular" water again until the softener recharges.

Run your numbers through Pool Math. Look at the CSI area towards the bottom. Share that with us and we can go from there with your "staining" or what ever it is.

Yea, I know how the water softener works. I wasn't planning on hooking up a hose to it or anything. Just replace the water slowly.

Scale, and it looks like you still have algae as well.

Your TA, pH, and CH were all very high which caused the scale to build up. There is nothing wrong with each of your numbers but when you combine them together, they potentiate eachother and make for water that is oversaturated with calcium carbonate. You can attempt to drastically lower the TA and keep the pH around 7.2 in hopes to dissolve some that scale but it will be a very long and slow process. Your best chance of removal is likely another acid wash but may not be possible based off the condition of your plaster.

If you had algae and only raised the FC to 12.5 then you did not kill everything in the water. With a CYA of 80, you should be maintaining a FC level of 34 until you pass all of the SLAM criteria.

Where are you located in CA? How old is the plaster?

Ok, I will get the pH down to 7.2. If it's a long process, that's fine. No one uses the pool right now, and hasn't for years. But when you say long, what do you mean by long? We can't do another acid wash due to our city not allowing us to empty our pool.

That would take forever. To lower your CH level, you would have to drain 75 % of the pool and that would get you to the 400 ppm range with your full water CH level. A residential water softener was not design to process that large of a volume of water. There are reverse osmosis companies locally that filter your water of the CH without draining the pool.

With a pH of 8 and your current numbers, your CSI is 1.12 which is double the level where scale occurs. Your CH is easily manageable (mine is higher than yours) but you can not have high calcium levels with very high TA and not expect scale to form.

Can't empty the pool like I said before. City isn't giving out any permits to empty the pool. My idea of using our water softener to place to the water, in my head was smarter because, there is 5-10 ppm calcium level. And the water coming from the city is like 200-220 ppm.

 

[bdavis466]

Yea, I know how the water softener works. I wasn't planning on hooking up a hose to it or anything. Just replace the water slowly.




Ok, I will get the pH down to 7.2. If it's a long process, that's fine. No one uses the pool right now, and hasn't for years. But when you say long, what do you mean by long? We can't do another acid wash due to our city not allowing us to empty our pool.




Can't empty the pool like I said before. City isn't giving out any permits to empty the pool. My idea of using our water softener to place to the water, in my head was smarter because, there is 5-10 ppm calcium level. And the water coming from the city is like 200-220 ppm.

It would take months to years to dissolve the scale and would require much attention. If you got the CSI low enough to do so, you'll also be dissolving some of the plaster.

High calcium levels get blamed for scaling issues but in reality its a combination of the pH, TA, CH and water temp (ultimately CSI). Lowing your calcium level alone will not solve the problem as you can still easily have scale with a CH level below 250. This is why frequent testing and staying on top of water chemistry is so important.

What city are you in?

 

[duraleigh]

+1 what bdavis is telling you. You are beating your head against the wall.

If you cannot think of any way to do a partial drain, I would suggest you forget about the stain removal project and simply start refilling your pool from the spigot with the softener. In a couple of years your pool should look great again and it will only cost you the price of the softened water.

As stated above, you must carefully monitor pH through out this time and keep it around 7.2

 

[Swampwoman]

Just a thought that might help on the ch end:

This tool has been used by other posters in the past to use MA to remove copper staining, but it should in theory also help remove scale buildup : Amazon.com: Purity Kit Underwater Acid Wash UAW: Home Audio Theater

In the event that the bottom staining is a combo of calcium scale and iron (eg are you on a well?) or copper, this approach may also clear up the stain if in fact the stain is not organic.

You mentioned that the staining doesn't brush off, but there is also some discussion of algae...perhaps performing an Overnight Chlorine Loss Test will help you get to the bottom of that one.

Lastly, is your softener a single or dual unit? I switched to a dual for constant regeneration capacity and was able to pretty much convert my pool to soft water over time. If yours is a single and if your ch builds up fast, upgrading to a dual system is an option, though not especially cheap do you have an outdoor spigot to whch the softener is actually plumbed?

Part 2: is it that you think you have mustard algae based on the stain? It usually favors shady walls...

Is your cya at 80 deliberately, eg for a SWG? Or if you're manually dosing, are you aware to maintain according to the [fc/cya][/FC/cya] -- Determning whether or not you really have algae (SLAM Process if you do) and getting your other parameters inline would be the first priority, then followed by the acid wash tool.

If you're not SWG, a partial drain and refill would als be good to reduce your cya level and make a slam, if needed, easier