1st Closing New Pool

[bcole]

Hello Everyone:

I recently had a new inground plaster pool installed in August of this year. I live in southeastern Pennsylvania. I had kept the pool opened until Nov 1st because I wanted to maintain the water balance ,especially the PH for as long as possible and allow the plaster to cure. I was having to dump in muriatic acid basically every other day to keep the PH down in the 7.6 range. All the other numbers were good. I was concerned about closing the pool and having the PH high for 4-5 months. I asked the pool builder about this and they basically said there is nothing else I can do and that everything would be OK. So I closed and winterized the pool on November 1st. I just took a look under the cover and tested the water and have a couple of questions.

1. The PH is now around 8.2 , and the alkalinity is 100. Do I need to address this somehow?
2. The day the pool was closed it was very windy and now there are a good amount of leaves on the bottom, is this OK? or will it stain the plaster?
3. There is a white residue covering the bottom that looks like DE to me but the pool company says its the winter chemicals they added, does this sound right?

Thank you for your help.

BTW- Pool is covered with a an Anchor Mesh Cover, that's supposed to block 95% sunlight

Bcole

 

[pwrstrk]

Welcome to TFP !!
I'm not 100% sure on all of my answers to your questions so I'll defer to one of the experts on new plaster pools.
Spend sometime reading in pool school over the winter. Lots of good info there. Have you looked into getting yourself one of our recommended test kit ? It's a must have for a trouble free pool.
Just wanted to welcome you aboard and hope you enjoy the forum !!
I forgot to ask if you could add your pool and equipment info to your sig. That'll help others help you better. Thanks !

 

[Johnl]

We live in an area (not far from you) that has very hard water, so high PH over the winter months can be a real issue. After opening our pool to a very bad scale problem one year, I started to regularly add a scale inhibitor product, like Scaletec. Ever since then we haven't had any scale when the pool was opened in the spring, even though the PH had drifted over 8.0 while closed.

Good luck.

 

[linen]

Welcome to tfp, bcole

I too am not an expert on new plaster, but could your last full set of test numbers including ph,TA,CH, Borates (if you use them), salt (if you added it purposely)?

White residue on the bottom would have me worried. Is it lose or is it fixed to the bottom (can you brush it)?

 

[bcole]

linen

The residue on the bottom is loose and can be just brushed around. The last full set of numbers was the day before I closed the pool and they were : PH 7.6 , FC 3, alk 100, Calcium hardness 240, cya 50.
The other day I lifted the cover back and tested the PH and it had gone up to 8.2. I thinking about putting some muriatic acid maybe once per week and circulating with a submersible pump to two. Do you think this would work? Would it circulate the water enough to disperse the acid?

 

[Leebo]

I too would worry about the white residue on the bottom. Depending on what it is, it could stain the plaster. I'd brush it the best you can. I'd avoid adding acid as there's little chance you'll circulate it good enough to avoid another staining issue. If you remove the cover the majority of the way however, adding MA little at a time and brushing the entire time could work.

 

[linen]

I thinking about putting some muriatic acid maybe once per week and circulating with a submersible pump to two. Do you think this would work? Would it circulate the water enough to disperse the acid?

Yes, others on this board have used this method. I would let the pump run for a couple of hours after adding the acid. You may not have to do it next year, but since your plaster is fresh and likely causing the ph to continue to climb up, it probably is a good idea to do it this year at least.

Fortunately your Calcite Saturation Inded (CSI), which is an indicator of potential for scaling, still looks decent at 0.35 (assuming your pool water temp is ~50F). You want to keep this between -0.6 and 0.6 for the most the time (higher than 0.6 is risk of scaling). What are you using to get your test numbers?

I would keep brushing the residue so that it does not park in one place. Any chance it is dry acid? What have you been using to lower ph?

 

[bcole]

linen:

Leslies did the full test numbers, and I have the leslies water test kit for the basic numbers. I use muriatic acid to lower ph. The residue was immediately noticeable after the pool company closed and winterized the pool. I called them and they said the residue was a result of the winter chemicals and was normal. I think he may have said it was no phos treatment, but not sure.

 

[linen]

Leslies did the full test numbers, and I have the leslies water test kit for the basic numbers.

I was guessing something like that. Most likely those numbers should not be trusted much. To proactively manage a pool, I would recommend you get one of the recommended test kits. Time and time again we see pool store results that are inaccurate.

I use muriatic acid to lower ph.

Good

The residue was immediately noticeable after the pool company closed and winterized the pool. I called them and they said the residue was a result of the winter chemicals and was normal. I think he may have said it was no phos treatment, but not sure.

I am not sure if a phosphate remover can damage the pool surface or not...I would think not, but I still would brush it around occasionally until it is dissolved.

 

[bcole]

linen

I just thought of an idea that might work. I have an Aquabot automatic pool cleaner, that runs off electric. I think it possibly could be the solution. I just plug it in and drop it in the pool with the pool cover on. It will clean the residue on the bottom of the pool, its supposed to filter down to .25 microns or something like that so it should clean that up. It addition it will pick up any remaining leaves, so that good. And lastly, it has a powerful motor that will help to circulate the water. As it runs along the bottom cleaning it sucks that water up through the filter and out the top of the unit at a powerful rate. This can help to circulate the muriatic acid. I think it could work, am I missing anything?

 

[Leebo]

Doing that plus running a submersible pump will work perfect. As you stated, it will clean whatever is on the bottom, plus help circulate the water.

I'd give that a go!

 

[bcole]

Thanks, its nice to be able to discuss questions here