Combined chlorine

[321done]

I have a 17,000 gallon hydrazzo pool with ultra pure auto uv water cleaner.
My water analysis:
Ta 150, ph 7.8, cya 45, calcium hardness 400, FC .5, Tc 1, combined chlorine .5. My pool place advised me to get rid of the CC by adding 3 lbs. of shock. Then correct my ph and TA after. I added the shock last night and now my FC is .5+, TC is between 1-1.5. It appears that its slightly gone up. How long after adding shock before I get accurate chlorine readings? Can I fix my TA and PH now or do I need to wait. This pool stuff is new to me and while I'm learning a lot, I have a long way to go.

 

[JasonLion]

You can go ahead and adjust your PH & TA if you want.

For the most part (salt and CYA are longer), you should allow an hour with the pump running after a chemical addition before retesting.

Any time CC is above 0.5, you should maintain the FC level at shock level (around 16 for your CYA level) until the CC level drops back down to 0.5. This is easier to do with a test kit that includes a FAS-DPD chlorine test (such as the TF100).

If your FC level 5+, or 0.5+? If it is 0.5+ you aren't using anywhere near enough chlorine. You need to shock the pool, see the instructions in Pool School for the correct way to do that.

 

[321done]

Since i have the Ultra violet water cleaner, I was advised to keep FC at .5 to 1.5. Could this be the case?

 

[jblizzle]

Welcome to TFP!!!

That FC is too low based on your CYA of 45ppm to keep the pool clear ... the UV may help some.

You need to follow the shock process to decontaminate the pool:
pool-school/shocking_your_pool

Read the rest of Pool School to get a better understanding of the chemistry while you are at it

 

[dmanb2b]

Is this an indoor or outdoor pool? Either way, with CYA at 45, an FC level of .5-1.5 is too low. UV systems have their place in indoor pools, but not required in outdoor pools.

 

[321done]

This is an outdoor pool and my water is crystal clear. What should I get my FC up to? I really appreciate the input. thanks!

 

[jblizzle]

Read Pool School and your will have your answers:
pool-school/recommended_levels
pool-school/chlorine_cya_chart_shock

You should never let the FC below 3-4ppm. But to go through the shock process you need to maintain a FC of 18ppm.

 

[321done]

I really appreciate the help! Thanks!