Beginner in Central Florida

[Florida37]

I just moved into my new house in Bradenton, FL. It has a small (probably under 10000 gallons) in-ground plaster/tile/concrete pool, built in 2004. Cartridge filter, pump running 10 hours a day. Water looks decent to my untrained eye. No algae. Previous owner used a pool service to clean pool / adjust chemicals once a week.

I got my new TF100 test kit today. Here are my results from tonight:

pH: 7.8
FC: 2.5
CC: 0
TA: 50
CH: 590
CYA: 45

From reading this forum, it looks like I need to add chlorine (bleach) to get my FC up to 4, and also add muriatic acid to lower PH to 7.5

I'm concerned about the CH. My city tap water has a CH of 160. If I want to lower the CH of the pool from 590 to 260, I need to replace 77% of the water with new tap water, according to the pool calculator.

My questions are:

1. Should I do a partial drain/refill? I would probably use the plastic sheet method to replace water, as I'm worried about high water table
2. If I am going to do a drain/refill, should I still adjust the PH and FC, or wait until after the pool is refilled?

Thanks for any advice. I'm excited about learning everything I can from this forum.

 

[frustratedpoolmom]

You are a fast learner ;-)

Your TA is a little low, the acid will lower the TA as well, so get some baking soda to offset the reduction.

The CH is high - I would suggest that you could just do a partial refill to get it down to say 400 range. Over time with small partial drains you can get it down - don't use Cal-hypo granular (prob what prior owner was using).

 

[Richard320]

Welcome!

You've done the math right. Those CH ideals are just that - ideals. Sometimes reality has to take over. Your low TA sort of cancels ouyt that highish CH. From my own experience, when CH closes in on 4 digits, it's almost impossible to maintain a neutral CSI. Play with the numbers on the pool calculator. Maybe take 25 or 30% out instead of 77%. Just do enough to stay in the safe zone and allow a little margin for error.

Also note that rainwater is CH-free. Doesn't it rain in Florida in the summer? Divert a downspout to the pool, you'll get 2 or 3 times, maybe more, water replaced than you do with just what hits the surface.

 

[BoDarville]

Florida37:

Welcome to TFP

First of all, congrats on choosing the TF-100. The investment in that kit will save you $ down the road.

High CH can be managed by paying attention to your pH and TA without having to do a dramatic high % drain & refill. Maybe drain & refill about a quarter of the water, then manage your pH and TA.

From reading this forum, it looks like I need to add chlorine (bleach) to get my FC up to 4, and also add muriatic acid to lower PH to 7.5

An FC of 4 for your CYA is the minimum. I would dose up to 6 ppm FC to allow for daily loss due to sunlight and see how that works for you. I would also target your pH in the 7.3 - 7.5 range. Your current 7.8 is higher than optimal for managing high CH to prevent scaling. And yes, you may need to use some Baking Soda to prevent TA from getting too low from the Muriatic Acid (MA) additions to lower pH.

Going forward, use liquid bleach as your chlorine source. There's no telling what the prior pool service used (could have been Cal-Hypo chlorine which would raise CH levels).

Also, having lived in Florida a while back, those summer thunderstorms will add fresh water to your pool and thus lower the CH ppm assuming pool is not enclosed in a Florida Room.

I would probably use the plastic sheet method to replace water, as I'm worried about high water table

You are way ahead of most by realizing this. Great job!

 

[Florida37]

Thanks for all the help. The test kit works great, especially the magnetic stirrer with the white LED lighting. I added more chlorine (bleach) and muriatic acid today. I also finally got my pool brush and vacuum, so I used them today as well. Here are my final readings today after adding the chemicals:

PH: 7.5
FC: 6
CC: 0
TA: 100
CH: 470
CYA: 40

Pools looks sparkling clean. I took a swim this evening. Water was very comfortable to eyes and skin.

 

[aseigler]

Hi Florida37,

FWIW, in central FL, I've found you can usually get the best deal on liquid chlorine at the pool store. Usually costs about $4 or $5 for a refill of a 2.5 gallon jug of 10.5%.

Good luck!

-aseigler

 

[Richard320]

Thanks for all the help. The test kit works great, especially the magnetic stirrer with the white LED lighting. I added more chlorine (bleach) and muriatic acid today. I also finally got my pool brush and vacuum, so I used them today as well. Here are my final readings today after adding the chemicals:

PH: 7.5
FC: 6
CC: 0
TA: 100
CH: 470
CYA: 40

Pools looks sparkling clean. I took a swim this evening. Water was very comfortable to eyes and skin.

Boy, I wish you'd have taken pictures of that tarp refill. They'd be really handy to use to demonstrate to others how to do it, picture being worth a thousand words and all that.