Biofilm? Gnats? Minute alien invasion?

[ShebaZa]

HI!

I'm a newbie, so far have been doing OK i think on opening, shocking, cleaning pool with no mishaps. Well, until a few days ago when we back washed the filter and forgot to rinse. Plumes of greenish water went spewing into the pool. Ick.

Water test at Leslie's results:
4/28
Fac 10
Tac 10
Ch 300
Cya 80
Ta 90
Ph 7.2
Copper 0
Iron 0
Tds 800
Phosphateso 300

4/7
Fac 7.5
Tac 7.5
Ch 300
Cya 99
Ta 100
Ph 7.4
Copper 0
Iron 0
Tds 700
Phosphates 200

I don't have printouts of prior two tests, unfortunately.

My questions are at this point is what should I do about high Phosphate?
Chlorine should I just stick with powder and not the tabs?
Ph on the edge of being too low, any suggestions?

And my alien question is regarding a film on the water surface that is brand new. Not sure what it is. But I did scoop a crazy number of suicidal earthworms out today who decided that death by drowning was preferably that being baby bird food. Grrr. oh and I did scrUbuntu the whole pool, back washed and rinsed after the green plume mishap. But this was four days ago.

 

[Texas Splash]

Hello and welcome to TFP! Well, you've come to the right place for help. But please understand our advise is for your benefit. Are you ready? Here we go:
1. You MUST have your own test kit. The pool store testing is typically not accurate and designed to sell products - expensive products. Make the effort to obtain one of the recommended test kits such as a TF-100 (link below) or Taylor K-2006C. The results above from the pool store simply are not worth adjusting to.
2. See all the vital links below in my sig? Review & save them. You will use them from now on.

Ignore the phosphates. In an algae-free pool they mean nothing. Get one of the right test kits (I highly recommend the TF-100 XL Option w/ speedstir). That kit will pay for itself in saved chemicals and time. Read the SLAM page and be prepared to follow the SLAM page once you get the right test kit. Pull the tabs and don't add powders. More than likely they've increased your CYA too high. Stick to adding only regular bleach. Just the plain stuff. Please update your signature so we know what type of pool you have and how big it is. Once you get the proper test kit, we can really help you.

By the way, your pH is okay for now - if we were to trust that pool store test.

Great to have you with us.

 

[YippeeSkippy]

Hey there ShabaZa Welcome to TFP!

As far as phosphates are concerned we don't worry about them! I like to refer to them as the "Phosphate Scare Card" that Leslie's pulls out when they can't talk you into buying anything else.

For explanation, phosphates are "food" to algae. If you keep your pool as we do here at TFP, it doesn't *have* algae, so who cares if the food is in there or not??

We also don't tend to believe pool store test results- for example, your CYA is "99" but that's only because the test tops out at that number. Unless you know how to do a diluted test to get the real reading, you're still in the dark about your CYA level.

I'd suggest a little of our PoolSchool Reading, starting with this: ABCs of Pool Water Chemistry then move on other topics in pool school such as :
Pool School - How to Chlorinate Your Pool
Pool School - Recommended Pool Chemicals

Bring back questions and we'll help you-

Maddie

 

[ShebaZa]

I do have my own test kit though I haven't ponied up yet for one of the big ones yet.

So what would be the recommendation if my ph gets under 7.2? Soda ash?

From the reading I've been doing it seems like the tabs raise the cya level so it being 80 current it is heading in the right direction that's why I was asking opinions on using the powder instead of the tabs to not elevate the cya again.

Anyone have a guess on the pool surface film?

15000 gallon chlorine
16x34 including steps
5 foot deep
Zodiac MX6 pool cleaner with leaf catcher
2x scum bugs

 

[Texas Splash]

So what would be the recommendation if my ph gets under 7.2? Soda ash?

Your pH should not drop under 7.2 unless you add muriatic acid to make it drop. But when pH does need to be raised, we do so with either soda ash, borax, or aeration.

From the reading I've been doing it seems like the tabs raise the cya level so it being 80 current it is heading in the right direction that's why I was asking opinions on using the powder instead of the tabs to not elevate the cya again.

I think you may be a bit confused. Yes, chlorine tabs/pucks do raise the CYA level. But using powder as an alternative to prevent CYA increase is not true. It depends on the powder you use. Many of those pool store products have stabilizer in them. The exception - Cal-hypo which add CH. Also remember this ... the CYA test at the pol store is one that is most-often performed incorrectly and causes some of the most common problems in pools. If you didn't test your own CYA, you're taking a big chance on adjusting or relying on their CYA test that was conducted indoors under incandescent lighting (not recommended).

Also, you state that your

CYA is 80 and heading in the right direction

Unless you misspoke, that's not true I'm afraid. As CYA of 80 is the high-end of the range for a salt water pool that uses a SWG to produce chlorine. From your pool info, you appear to manually chlorinate your pool. Your (summer) CYA should be more ideally be somewhere around 50 - give or take about 10 ppm depending on the weather. The only product you should be using to increase FC for sanitation is regular bleach. It's the only product with no CYA or CH side-effects, and usually the cheapest to use.

You mention you do have your own test kit, but I suspect it's not one of the recommended ones, nor does it have the FAS-DPD portion required for precise FC testing and to conduct the "SLAM" I mentioned above to remove that algae in your pool. You can get the FAS-DPD HERE.

As for the film you mention, it's a toss-up between any pool store products that may have been used in the past and/or algae-related. We don't have accurate tests to go on, but your descriptions in post #1 confirm you have algae.