Sudden ph problem causing terrible discolorations

[dnico33]

[attachment=0:2cmyd3px]Plaster problem.jpg[/attachment:2cmyd3px]I haven't had the "start up" promised by my pool builder concluded yet. Everything seemed to be going fine, if not way too slow on him hooking up all the systems. I started to have my doubts about him early in the process, but by staying extremely vigilant over construction I caught multiple problems while it was still early enough to easily correct them.

Here's the chronological order of what has transpired over the last few days.

Friday: Measured ph and chlorine, chlorine was fine but ph was around 7.8 and my plaster company said to keep it at 7.4, I added acid as I'd been doing pretty regularly after my daily checks. Spoke with him and he told me he had the acid "Sense and Dispense" system by Hayward up and running and I should leave it alone and let the system take over ph adjustment.

Saturday I checked it and it was still high but in the ball park but didn't do anything as per his instructions.

Today, Sunday, I got up and the pump was running on high but no water was moving and there was staining all around the main intake at the bottom of the pool and for about a two foot wide strip all the way up to the shallow end, visible in the picture. Also just the very bottom entry step had discolored the same way (lower left corner).

He came after I left a 911 message, accused me of adding acid against his instructions, and added soda ash to bring up the ph. In a few hours I'm checking it again and adding more ash if necessary.

Here's a pic of the staining, I have no faith in this guy at this point. I am calling the plaster company in the morning, but maybe someone has some advice on what I need to do in the short term. He says the "Sense and Dispense" system did not add any acid, but I have no way of knowing. Thanks.

 

[JasonLion]

You didn't mention what the PH was today. Also, can you describe the discoloration/stain. It looks like two wide black streaks in the photo, which is a very strange pattern for stains to appear in, but perhaps I am mistaking a shadow for the real discoloration.

 

[dnico33]

You didn't mention what the PH was today. Also, can you describe the discoloration/stain. It looks like two wide black streaks in the photo, which is a very strange pattern for stains to appear in, but perhaps I am mistaking a shadow for the real discoloration.

ph was 6.6 when I first checked it not too long after soda ash addition. Went up to 7.0 after 2nd add and 7.3 after third add. Then small add this morning and it's now all the way up to 7.7, it had been running high constantly since start up I needed to add acid just about every day to keep it around 7.4.

The stain is what you see running from right to left for the full length of the pool, at the deep end which is 5'10" it forms a rectangle around the intake drain.

A few hours after the first soda ash addition (6.6 ph then) I brushed the bottom step (lower left corner of pic) and all the discoloration came off. On the rest of the area some of it comes off after repeated brushings, but not like on the step.

With the ph back to 7.7 I'm wondering if I should put a little acid in
ORP was in mid 400's yesterday and is now at 220 mV if that helps at all.

Builder has yet to return a call today and we might be headed for court so any ideas on what to do to stabilize this situation and finish equipment hook up would be helpful. I am not a handy guy.

 

[JamesW]

Do you have an in-floor cleaning system?

Is that back tiled wall a fountain?

 

[JasonLion]

Lets start with the basics. Keep the water moving. Keep the PH between 7.2 and 8.0. Add some chlorine regularly. The simplest way to add chlorine is to keep two or three trichlor tablets in the simmer(s) (but only while the pump is running 24/7 during the first few weeks).

That was a fairly drastic PH reduction. There aren't very many ways for the PH to get that low, as it would likely take a couple of gallons of muriatic acid. Is it possible that acid feed system feed it's entire tank of acid into the pool?

I don't like the sound of the pump running but no water moving. Most likely that means the pump lost prime. Was there a lot of air in the pump strainer basket? If the water level is too low in the skimmer, the skimmer basket lid is not sealing correctly, or there is a suction side air leak, air can get into pump strainer basket and cause the pump to lose prime.

It isn't clear to me what caused the stains. Keep brushing and see if there is any progress over a couple of days or not.

 

[dnico33]

Yes to in floor (A&A), yes it could have dumped a bunch of acid in b/c this guy made a mistake and now he's hiding and trying to avoid it. The skimmer area was making a sucking noise but now it seems to be running fine. Running out to get a wire type brush as a local service suggested, that it's better than nylon and still will not hurt colored plaster. Thanks for your help, I'll check back before I start with with the new brush.

 

[JamesW]

It looks like whatever caused the stain came out of the in-floor pop-ups. It looks like something of higher density than water. I'm thinking that it might have come out of the pop-up heads while the pump was off and then proceeded to flow down toward the main drain and pool there. It could have been acid, but that's an unusual color stain. Perhaps it's copper(II) oxide (aka cupric oxide CuO) if you have a heater and the acid somehow got in the heat exchanger and dissolved some of the copper.

Can you post another picture of the entire pool?

 

[dnico33]

This must have been the result of an incompetently installed Sense and Dispense system, which sent way too much acid in through the in-floor system as was suggested. Thanks for seeing that.

Stain is dissipating through repeated brushings and I have a new competent pro on the way to finish setting up the systems.

Again thanks guys for the help!

 

[Melt In The Sun]

Crikey...
Where is the sense/dispense located in the plumbing? Is it before the heater? I'm asking because that stain, as JamesW said 2 posts up, looks like the acid ate something like a heat exchanger.

 

[JasonLion]

If the acid feed was locked on and the pump was off it could well have slowly pumped acid up through the in-floor cleaning jets.

 

[Melt In The Sun]

I bet you're right about the main pump being off Jason...it looks like it oozed out rather than was blown out. I still would be very worried about what was dissolved to produce that stain on the plaster. Something metal, for sure.