Relatively new pool owner with a few questions


Jun 9, 2007
We bought a house that has an older gunite pool that has been painted with chlorinated rubber paint. We have it in pretty decent shape, but it is a hit and miss deal to get good looking water over the past three years. I usually just head over to the pool store each year with a water sample, they put the sample into a bunch of vials, drop them into the computer tester, and give me a print out of what we need to do. I would like to be more knowledgeable about our pool and have a few beginning questions. Below is our pool specs followed by some of my beginning questions.

20' by 40' concrete with rubber paint
I calculated the volume and came up with 50,000 gallons
I can't tell my pump HP or flow because all of the ID tags have worn off
It has two 1.5" suction lines and three 1" return lines
The filter is ultra old (some kind of cloth bag, but seems to work)

1. We are going to replace the failing filter. I am planning on going with the Hayward 6020 Vertical Grid DE Filter, but I am also considering investigating a sand filter with zeolite. Any thoughts? I know that there are varying opions, but I am wondering if I will be making a mistake considering the type and size of pool I have.
2. Can I get a filter that is "too big", if I am not so concerned about cost?
3. What would be a good test kit for a beginner.
4. When just starting to get your water under control, what is the first thing you look to adjust. I realize that it depends on your test results, but I am more looking for a sort of ranking as to which item you look at first to see if it is OK, and then so on down the list.

Thanks in advance for you time to answer my questions.


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Welcome! Feel free to ask all the questions you want to.

Your pool would have to be quite deep to have 50,000 gallons. What depth is it?

There is no truly correct choice for type of filter, they each have advantages and disadvantages. Personally I like my regular sand filter. Any filter will work if it is large enough.

The only way a filter can be too big is if you either can't afford it or it doesn't fit in the space you have. In every other way it is always better to get a larger filter.

I would go straight to the TF Test Kit. You don't need to use all the tests right at first but you will have them if you need them. Right at first limit yourself to the Taylor TC and PH kit that comes inside the TF Test Kit, when you are comfortable with that try the others.

PH is almost always the first thing to look at, then chlorine. You will want your CYA to be non-zero fairly quickly, but getting it to the right place will take time so don't worry about that at first.


Jun 9, 2007
I thought that seemed like a lot of water also, but it is 10.5 feet in the deep end. The previous owner needed to have a one meter board. The shallow end is a 4' deep. I also heard that certain sand filters can allow some zeolite to get back into the pool. Since I am buying a new filter, if I go the zeolite route, I wanted to get one that best would work with that filtration medium. Thanks.


Well-known member
May 9, 2007
Welcome to TFP Dewey.

The volume of your pool calculates to 43,500 gallons using the calculator built into the Bleach Calculator. 20 feet by 40 feet by 7.25 feet average depth (10.5 + 4.0 / 2 = 7.25) Pool Volume is one of the options under the More Calcs in teh upper left corner.

Here is the link to download a copy of the Bleach Calculator

Here is a link to read more about the TF Test Kit that was mentioned above.

Happy Swimming in your Trouble Free Pool