Algae bloom question

[blind luck]

I switched from cal-hype to dichlor because my hardness was high. Now I have an algae bloom. Can't get chlorine strong enough in my area. would need a truck load of what's available. Is it safe to go back to cal- hypo? Last used dichlor 4 days ago.
Should I do a partial drain first?
calcium hardness: 563
Ph: 7.5
Alkalinity 76
Cya 4.8
FC : 4.07
TC: 4.07
Sand Filter

 

[Texas Splash]

Welcome to TFP! To answer your question we in-turn have a few questions:
1 - What kind of pool & equipment do you have? Update your signature - see mine as an example.
2 - What test kit are you using? Be sure to add that to your signature as well.

If that is pool store testing, there's not much we can accurately say at the moment. Store testing is often flawed. But if your CH level is close to that number, the last thing you need is more cal-hypo. I doubt your CYA is 4.8, so that needs to be addressed. Liquid chlorine is always the best product to use for a SLAM Process.

 

[Texas Splash]

Also be sure to visit our Pool Care Basics page for lots of great info.

 

[blind luck]

Apologies.
In ground plaster pool.
10 percent hypochlorine is the best I can get. Frequently out of stock in my area. Miserable pool season for owners.
I realize cal-hypo raises the hardness.
Just about out of other options.

 

[Texas Splash]

Understood. It may be the least of the evils you have to work with. Do the best you can with what's available. Remember that regular laundry bleach is the same as pool chlorine but at a weaker % strength. If you do grab some bleach bottles, make sure they are plain/regular. Do not use scented, splashless, or Clorox brand laundry bleach. As you find your CH climbing, it will be even more important to properly manage the pH and TA levels to prevent scaling. A TF-100 or Taylor K-2006C test kit will help you do that. To conduct a SLAM Process, you should have a minimum CYA of 30 with an elevated FC SLAM level of 12 per the FC/CYA Levels. Hope that helps.

 

[blind luck]

Thank you.
Should I partially drain before the slam?

 

[Texas Splash]

Should I partially drain before the slam?

In some cases that is certainly appropriate. Depends on the cost of water versus cost of chlorine/bleach. It can help expedite the SLAM Process for some owners. Be mindful of how much water to lower/exchange if you believe you have a high water table in your area.

 

[blind luck]

So the app. says to add 205 ounces of 10% chlorine to get to 12ppm from where I am now. That sounds like not enough. Should I not use the app for slamming.

 

[mknauss]

We cannot help without complete information. Please fill out your signature.

Edit—. I now see the signature. My apologies.

205 ounce of 10% adds 8 ppm FC to your pool volume. How much FC rise do you want.

 

[blind luck]

Done.

 

[blind luck]

Have an algae bloom. Need to get it from 4 to 12
I guess that is the right amount then.

 

[mknauss]

Then that amount works. SLAM is a process. You test FC and add liquid chlorine every few hours. You need a proper test kit to be successful.

 

[blind luck]

Thank you sir

 

[jeffchap]

What are you basing your SLAM FC level of 12 ppm on? Have you obtained a recommended test kit yet and gotten an accurate CYA reading? Without that, you're just taking potshots in the dark.

 

[blind luck]

Test kit yes. Based on test kit readings and pool math app.
Today FC is 10 and Ph above 8. Still green.
Alkalinity 70
Suggestions?

 

[blind luck]

CYA 40

 

[Texas Splash]

Before the SLAM Process, take this moment to lower your pH a bit. An FC over 10 makes the pH read high, but if it truly is well over 8 you should the pH down to the lower 7s if possible. At least mid-7s. Then using the FC/CYA Levels, water with a CYA of 40 requires a SLAM FC level of 16.

 

[blind luck]

Thank you

 

[blind luck]

FC-13
PH 7.5
CY A=50
Still green.
Been using a secondary test for cya. Updated taylor kit to one you suggested. Be here in two days. Was 105F so could have had evaporation leading to higher CYA I guess.
Round 3 tonight. Hopefully get there.
Is it safe to use robotic cleaner at those chlorine levels? Have to get in the pool to to hook up vacuum line. Pool built in 1979. Have wet suit,

 

[mknauss]

FC between minimum and SLAM level based on the CYA is safe to swim in. Sounds like you have a pressure side or suction cleaner not a robot. It is fine in the pool.