Constant battle with algea

[SWnic]

This is my fist post to TFP. I have read all of the pool school information several times, and I think I understand all of the testing and treating processes pretty well. This is the second year with our new pool, last year it didn't get finished from construction until August, then closed in November. This year, I opened it in May, still open. The problem I have, is that I continue to battle green algea. I will slam, test, verify, filter , believe I have it all sorted out, and seems like I can't get a full week, before the green starts showing up again. I test the chlorine daily, and yes I have the good kit with the DPD/FAS test. My water itself doesn't seem to get green, just the deposits that grow on the bottom of the pool. What I really don't understand, is I have been keeping the free chlorine level at around 10 ppm, and it's still growing?? I really don't get it, although I did just pull the steps today, with green under them.
I'm currently slamming again, so chlorine is up to 26 ppm, I have CYA of about 50, PH is 7.5 TA is 80. The guy at the local pool store says problem is phosphates, although didn't say what that level was when I had them test the water (i always do my own testing, so this was a one-off event). Is it me, or does anyone else out there have this continual battle going On? I either don't have adequate equipment, or I'm simply doing something wrong, no matter if I think I'm not.

 

[mknauss]

Welcome to the forum! :handshake:

Great on reading up on Pool school. What test kit are you using? Please add it to your signature. Also please post a full set of test results.

Read SLAM Process. Focus on the maintain. You should be testing your FC and dosing back to shock level every couple hours until your FC starts to hold. Then follow through until you have passed the three criteria.

 

[duraleigh]

Welcome to the forum

TFP often gets similar posts. The very short, almost unbelievable answer is chlorine. Algae simply cannot survive in a properly chlorinated and maintained pool.

Is your pump running 24/7?

Is your filter increasing in psi and being backwashed?

Are you brushing and vacuuming? How often?

I will add that your Intex filter is notoriously inadequate to do a proper SLAM.....but it should make it.....just very slow.

PS - Since you have a good kit (tell us the make and model) You should NEVER let a pool store test your water. Learn to trust your own testing.

Reread the SLAM process in Pool School. Chlorine kills algae.....never think it won't. Try to figure out what you might be doing that is not allowing you to get adequate chlorine in contact with the algae.

 

[domct203]

Welcome to the forum!

What is your CC level?

Once the pool is completely free of algae, we will help you keep it that way.

I had your same filter and pump on my 6700 gallon pool and found it’s overall performance marginal. It took forever to vacuum, and required backwashes during vacuuming.

How often do you brush and vacuum?

 

[SWnic]

Welcome to the forum!

What is your CC level?

Once the pool is completely free of algae, we will help you keep it that way.

I had your same filter and pump on my 6700 gallon pool and found it’s overall performance marginal. It took forever to vacuum, and required backwashes during vacuuming.

How often do you brush and vacuum?

My test kit is the TF 100. I just tested it as the sun set to check the chlorine loss overnight. I'm showing 20 ppm free chlorine and .5 ppm CC. I do brush, usually when I start seeing something, same with vacuuming. I do wonder if the Intex pump is enough for the pool. I also suspect that the steps in the pool block or disrupt flow / besides harboring green under them.

 

[duraleigh]

If you brush and vacuum after you "start seeing something", you are actually too late. Do both before you see algae and make it part of your maintenance routine after your pool is clear.

 

[domct203]

If you brush and vacuum after you "start seeing something", you are actually too late. Do both before you see algae and make it part of your maintenance routine after your pool is clear.

+1
Brushing your pool is like brushing your teeth, it is a preventive measure that should be done regularly.

Would you please list a complete set of test results including:
FC
CC
pH
TA
CH
CYA

Also, are you doing the CYA test outdoors on a bright sunny day, back to the sun, reading the vial in your shadow at about waist height?

 

[SWnic]

I'll get a full set of readings and post shortly. I did test chlorine this morning for the overnight test and lost 2 ppm. I have already added a bit more chlorine to continue the slam. Message understood about brushing, thanks guys. Also, I never knew the method you mention on checking CYA, but will try it this morning.

 

[domct203]

CYA is a bit of a challenge at first, I hope this info helps.

Pool School - CYA
[edit]
I find it easier to fill the view tube to the first mark, then glance, not stare. If I see the dot, I fill to the next level and glance for the dot. I continue until I don’t see the dot at a glance. If I stare, my eyes play tricks on me. [/edit]

Ask any questions you may have about the testing, we’re here to help you enjoy that pool.

 

[SWnic]

Ok, here is the full set of readings. I see CYA needs to come up for sure. I'm curious as to why the CYA level in a SW pool needs to be so much higher than a manually chlorinated pool??

FC 21
CC .5
PH 7.5
TA 80
CH 125
CYA 35 - 40 ish (done several times w/ same mixed sample)

Water is looking good this morning, pretty clear, pump in steady 24/7 operation

 

[mknauss]

At this point in the season no reason to raise your CYA. The CYA level is assist in maintaining the FC level during high UV (summer) so you can leave it as is. Use 40 ppm CYA to determine FC levels.

pH test is invalid when your FC is over 10 ppm.

Maintain your FC at 16 ppm until you meet the three criteria for a successful SLAM described in the article.

 

[SWnic]

At this point in the season no reason to raise your CYA. The CYA level is assist in maintaining the FC level during high UV (summer) so you can leave it as is. Use 40 ppm CYA to determine FC levels.

pH test is invalid when your FC is over 10 ppm.

Maintain your FC at 16 ppm until you meet the three criteria for a successful SLAM described in the article.

Ok, I'll do all you suggest. Thanks for your help.