High PH - Feeling stupid

[waterbear]

CarlD:

I think I am confused in general on testing kits for clorine. I keep reading that Ben's test kit is only accurate up to 15ppm and it is a FAS-DPD test isn't it? (I don't have it so I don't know). Above 15ppm - doesn't it start to bleach the reagent so you can't read it? The OTO clorine test doesn't bleach - but it only reads up to 5ppm?
The DPD drop test (such as the one in the Taylor K-2005 kit) for FC/TC can bleach out. It is not the same as the FAS-DPD titration test that is in Ben's kit.
But then I read that the FAS-DPD is for high clorine readings.
Correct. (or you can use OTO with dilution of the sample but it will only measure total chlorine)
So my confusion is that if you have to shock your pool to a theoretical 25ppm, what do you use to measure it?
FAS-DPD
(this may be a totally stupid question, and if my pool was ready and I had the tests- it might make more sense)

Hope ths clears things up.

[Simmons99]

It sure does - thanks!

[Newbie65]

Okay, folks here's the newest readings:
TC = 5 after dosing and holding at 15 ppm for 2 or 3 days
PH = 7.2 holding steady after first dose of muriatic acid at beginning of thread
Alk - 180 not really a problem (I don't think) always runs high
CYA - 30 - 50 last time I checked w/strip test

Can't afford Ben's kit right now, daughter just enrolled in college!

I have a 27,260 gallon AG pool, 1.5 hp pump, 300lb Hayward 244T sand filter, w/2 skimmers and 2 returns.

This morning is the first time since May 18 that I have been able to see the bottom. Let me say thanks again to all who helped! My problem now is, I can see light tan stuff on the bottom. The water is not completely clear but clear enough to see the stuff. I got home and vaccumed to waste until my water level caused me to stop. I wasn't able to make a very big dent in the tan stuff, seems like it just moved around.

Since the tan stuff on the bottom is probably algae should I go ahead and raise my chlorine level to 15 or 20 again or just keep vaccuming when I get more water back in the pool?

Do I brush and stir everything up again? I'm really not sure what route to take and I've got bleach bottles coming out the wazoo! Recycle day can't get here soon enough!

Hope someone replys soon, it'll be dark soon.

[Pamsel]

I'd like to add a question to this thread. I also have very high PH and over the last 30 hours have put in a total of 1 gal muriatic acid. I have a 14,500 gal pool. So far, the PH has not come down and my TA is also very high -320

I think I should have dumped in a half gallon of acid to start with, but now that I've put a gallon in since noon yesterday, do I wait or should I still go dump another 1/2 gallon in?

I'm maintaining my chlorine at about 10-12ppm - I need a kit that is accurate over 5ppm. Can someone tell me exactly which of Ben's kits to buy? It looks to me on the site that the main one is no longer available?

Thanks!

[mbar]

I asked Waterbear to look at this post about the rising ph and alkalinity, since he is great with pool chemistry :


Marie, I went through the thread , posted, and hopefully explained a few things that are going on. The big red flag for me was '3 month algaecide'. All the ones that I have seen like this are copper! Might explain part of the green water, not to mention the iron! This is YOUR area of expertese so the ball is in your court!

As far as the alk and pH...2 possible reasons.
1. It can take a LOT of acid to overcome the high ALK, which is a buffer that keeps the pH from changing, before you start to see the pH move at all.
2 High chlorine levels will interfere with both ALK and pH tests. pH tests will read 8.2 even thoough the pH is much lower because the phenol red has been converted to chlorophenol red which is used to test the pH range of 4.6 to 6.8 and gives the same color at 6.8 that phenol red gives at 8.2! All you really know is that the pH is somehwhere above 6.6![/QUOTE]

[aylad]

Pamsel,
It would keep things a lot less confusing for the responders if you would start your own thread instead of adding a question to an existing thread....you're way more likely to get good answers, and the responders are less likely to get your situation confused with the original poster's problems..

To answer your question, you need to keep adding the acid until your pH starts to move, because it has to come down for your alk to be lowered.

And to measure Cl higher than 5, you can use CarlD's dilution method for a ballpark Cl reading with the test kit you have, or you can get exact measurements up to 50 ppm from the dpd/fas chlorine testing in the PS 234.

Thanks

Janet

[Pamsel]

Thank you Janet, I will stick to my own thread. I guess I was reading and saw this thread which seemed similar to my problem and jumped in. I will remember not to "cross over" from now on.

Thank you Marie, also for your help here. Now, I'll get back to where I belong!