Pool company can't get the water right in our new pool and wants to take out the glass media and put sand in possibly.


Jul 6, 2020
Cincinnati, OH
I will try to keep this short and sweet.
18x36 6'. Saltwater with IC40, Pentair SD-80, Heat pump (have been using somewhat), Pentair VS superflow. In SE Ohio.
Pool was finished a couple of weeks ago. I had been cleaning it everyday during the construction because I was seeing dirt in the bottom weeks before it was finished. (It wasn't dirt we found out, I am colorblind. It was mustard algae I believe after doing some research, based on how it sat in the pool).
I had issues getting a real test kit as the first one had opened up during shipping and had to be returned, so I was going to Leslie's Pool Supplies near me and getting the water tested starting almost two weeks ago. The levels were way off for just about everything. I informed the pool builder they needed to get the water right before I would give them the final payment. They started treating it a week ago and have been adding crazy amounts of chemicals as of the past couple of days. They are now saying they haven't seen anything like it before in 20 years. The chemical guy just talked to the owner of the pool company and was informed that there was an enzyme that need to be added for the glass media that we used. (I forced them to use it, I am the very first customer of their's to use glass in the sand filter). He also mentioned that if they can't get this under control, they are going to want to swap out the glass for sand, cause that must be the problem since they have never seen this before and they have never used glass before. I do not believe that glass vs sand could even remotely be the problem, but I am open to the idea if anyone else can back it. .
The company is reputable enough, they have been building pools for 20 plus years successfully as far as I can tell. I believe they know what they are doing.
Here are the levels from the first time I had it tested.
FC=0.003 !
Total Alkalinity= 194 !
Phosphates=2832 !
I know, right?
The phosphates kept rising even though there has been no fertilizer anywhere near the pool and we tried noPhos. I know everyone says they don't care about phosphates, but in the thousands? The ants were committing suicide by the millions in the pool, but has lessened up. We have two large Rose of Sharons close to the pool that started flowering a couple of weeks ago. We do have lots of trees in our yard, but not super close to the pool and there haven't been a lot of leaves in it, nor should they be pollinating right now anyway. Within a week, the phosphates had reached 3100 and I stopped testing cause they were dosing it Dang near everyday anyway.
Within a week of the first test, the here are the results.
FC = 2.58
pH = 8.1
Alkalinity = 149
Calcium = 182
CYA = 34
phosphates = 3127

Sorry if I rambled or missed important info. I was up 24 hours straight for work and just woke up after 2 hours of sleep to the pool guy knocking on my door to tell me this.


Well-known member
Jun 16, 2019
Hey explorer !! So there is a very good chance that either you never fully cleared the first algae problem, or it’s back. Use PoolMath To add 5ppm of FC as the sun goes down and perform an Overnight Chlorine Loss Test to test for organics. If the FC drops 1 or more, it’s time to SLAM Process. Did the reliable test kit come ? You’ll need your own kit handy for multiple tests daily for the SLAM to work. Besides the pool store being unreliable, you won’t want to run there many times to get lackluster answers.

I would ditch the glass media either way. The absolute best thing that anybody can say about it is that sometimes it works as well as sand. They can never say it works better than sand. So why even bother if it’s only equal, or probably worse.

To recap, It’s either algae, The filter media, or both. ask away with any questions and we got you.


Jul 6, 2020
Cincinnati, OH
I may have not done my due diligence, but I have never read anywhere on this site or any other, that glass wasn't superior to sand, other than cost. Some quick research still shows the same thing.
I agree that the algae was never cleared. I wish I had realized what it was a long time ago and mentioned it to them. We were basically cleaning it up everyday before the pool builder saw it. They were not doing there due diligence either though, they should have been testing it from the beginning and treating it until handoff.


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
The glass media will work. Our Australian friends use it vs sand. It is not better, but it does work.
You need to follow the SLAM Process. To do that, you need a proper test kit. I suggest the TF-100 A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols.

While you are waiting on your test kit, add 5 ppm FC worth of liquid chlorine / plain bleach to your pool each evening with the pump running. This will replenish the FC lost each day to the sun and also inhibit any algae in the water from growing further.

The above cannot be done by a pool maintenance company. To be honest, you are at a decision point, follow TFPC and do this your self, or step back and let what happens happen by the maintenance company. Of course, you pay for everything either way.


LifeTime Supporter
TFP Guide
Feb 6, 2015
Chandler AZ
Do you have one of the recommended test kits? See Test Kits Compared
I recommend the TF-100 and Speedstir. It provides more of the testing reagents we use most.

Your test results look like pool store testing. We can certainly help you get your pool water balanced and clear if you can provide results from your own testing.

Water temp

I kind of doubt your pool company even knows what SLAM means - let alone how to do it correctly. See the SLAM Process and compare to what they are doing.

Brett S

Well-known member
Mar 15, 2019
Honestly, I have a couple of thoughts on this. First, neither glass nor sand will cause or fix water chemistry issues. If you like the glass media then keep it. If you want the more conventional sand, then have them switch it out. It certainly sounds like they’re willing to.

Additionally, there’s nothing about a pool that will cause weird chemistry issues. It’s not like the pool builder did something wrong while building the pool that would cause these issues. Assuming that you’re a first time pool owner, I know the thought of managing the water and the chemicals can be kind of scary, especially when you’re seeing professionals struggle with it. However, I honestly think the best thing you could do at this point is pay the pool company and tell them “Thanks, but we’ll take it from here”

The pool management technique that we teach here on this website is vastly different than what pool stores and pool builders use. (And I don’t believe for a minute that the pool builder is slamming your pool. Slamming is not shocking and the slamming technique is almost impossible for a pool professional to do because to do a slam the pool needs to be monitored and chlorine added every few hours. A pool professional is not going to sit at the house all day to keep monitoring the pool. They will shock the pool by dumping in a bunch of chlorine and leaving, but that is not a slam and will not fix the underlying issues).

Even if you let the the pool builder fix the algae issue and balance the water to their standards, as soon as you take over and start managing the pool you are going to discover that they have added things to the water that are unnecessary and we would never use. If they add heavy doses of algicides, for example, they could be adding metals to your water that can cause problems for you for years.

Like I said, I know it’s scary, but I am 100% confident that with the help of the techniques taught on this web site (and the volunteers here in the forum) you can fix the issues you are seeing in your new pool by yourself faster and safer than letting the pool builder take care of it.

But you need to make a decision. You can’t take some advice from the pool builder or pool store and some advice from the this web site, because that is only going to cause more problems. Our methods are not compatible with pool store advice. So if you want us to help you fix your problems you need to be able to fully commit to the trouble free pool methods and not let your pool builder add any more chemicals to your pool or take any more water to the pool store for testing. You need to use your own TPF approved test kit to test your water and only use chlorine to fight the algae.

You can do this and we can help you do it, but you need to decide how you want to proceed and commit to that choice.
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Well-known member
May 7, 2020
Lathrop, CA
This is a sad situation to be in for sure with a brand new pool. And pool builders are just that. Read up on the filter media, if sand is better get your PB to change it.
Beyond that, I think you're better off taking the matters into your own hands and following TFP's SLAM Process. Your PB will follow the conventional practices and will in most likelihood continue dumping in all sorts of chemicals in hopes the problem goes away for a short while.
But once they declare their "victory" and leave, algae is most likely to come back.


Jul 6, 2020
Cincinnati, OH
Afternoon everyone. I agree that that it will be up to us to maintain this pool based on the techniques taught here. In regards that the pool builders did not do something wrong while building the pool, I disagree. They filled it with water, then continued on with construction without any testing and getting the water in the right place. They are responsible for the project up until handoff and at handoff I told them to fix the water at their cost, because it was unacceptable.
We were gone over the weekend, just got home and the water looks much better. I have received my K-2006C kit now and will be doing lots more reading, testing and following of the techniques taught here. It is daunting, never had a pool before, but we will persevere. Thanks everyone and I imagine this will not be my last post, but I will be better armed and educated to maintain it on my own now.


TFP Expert
Mar 2, 2011
I know everyone says they don't care about phosphates, but in the thousands?
Phosphates are reported in ppb (parts per billion) instead of the normal ppm (parts per million) that everything else is reported in.

So, while the number looks big, it's really not.

3,000 ppb is only 3 ppm.
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Costas > DownUnder

Bronze Supporter
Dec 17, 2017
Adelaide | Australia
they are going to want to swap out the glass for sand, cause that must be the problem since they have never seen this before and they have never used glass before.
They are just (incorrectly) guessing as they are stumped and have no idea how to proceed.

Filters are effectively a mechanical device ie they simply filter particles in our water simply by passing water through tiny spaces/gaps that form around/within the media.

These spaces are generally smaller than than any visible particles and that is how they work - no real different to a tea strainer....:)

Many pool owners (and shops) make the mistake of thinking that filters clean out biological (algae etc) growth in pools - they simply do not.

Chlorine is what kills off algae.

With incorrect chlorine levels (In your case - too low), algae will take hold and no pool filter will ever kill off this algae.

You need to follow Marty's advice in post #5 to get a handle on your water...

BTW - Marty is correct in stating that down here in Australia, glass media seems to be very popular (i'm using it) and the media itself is not your issue.
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Silver Supporter
Aug 22, 2017
West Palm Beach/Florida
Also please fill in your signature, it will help the experts here through the process. We need to know what type of pool, if it is plaster/pebble and your finish is also only two weeks old that is important to know.

Brett S

Well-known member
Mar 15, 2019
In regards that the pool builders did not do something wrong while building the pool, I disagree. They filled it with water, then continued on with construction without any testing and getting the water in the right place. They are responsible for the project up until handoff and at handoff I told them to fix the water at their cost, because it was unacceptable.
I think there are a couple issues with this. I do agree that in a perfect world it would be best for the pool builders to hand over a pool with perfect water. And I do agree that it would be fair to expect them to fix the water in your pool before they hand it over.

However, what I’m questioning is whether you actually *want* them to do that. The method that the pool builder will likely use to try to fix the water is dumping a bunch of chemicals in. As you stated above, they said “we’re throwing the kitchen sink at it”. A lot of the chemicals that they will use are things that you don’t want in your pool. Things like clarifiers and flocculants that can cause issues with your filter or things like algicides that contain metals that can cause staining in your pool (and in your hair).

These are all things that we at troublefreepool strongly recommend that you stay away from because they can cause a lot of problems. Once those things are in your water, then the only way you can get them out is by changing your filter media (in the case of clarifiers and floccuants) or changing out your water (in the case of metals). We at troublefreepool would use only liquid chlorine in a SLAM to fix the algae issues. This will not cause any long term problems with your filter or water quality.

However, the problem is that our methods are not widely accepted by the pool industry while dumping in a bunch of chemicals is standard practice in the industry, so I don’t think you will really have any recourse against the pool builder for using those chemicals that you don’t want in your pool. If you go to almost any pool store or pool professional that’s what they will recommend.

I also think it’s very unlikely that the pool builder will take the time to read through our web pages and pool school articles and follow our advice to clear up the pool using our methods. Our methods absolutely work, but doing a proper SLAM can be time consuming at the start because you need to keep checking the pool ever few hours. There’s no shortcut to this or sending someone over to check once a day or once every few days. Our methods work well for a homeowner who can take the extra time, but they don’t work well for a pool professional who can’t just sit and babysit a pool for a day while the SLAM is starting. (And just to be clear, I’m not talking about normal every day maintenance here. Once the SLAM is over and the algae is gone you don’t need to spend this much time maintaining the pool, it’s just the SLAM to clear up the water that is time consuming.)

So really, what I’m saying here is that while I can absolutely understand why you want the pool builder to clear up the water, if you just take over now and work to clear up the water on your own then you will know exactly what is being put into your pool and have much better quality water in the long term.

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
SouthWest Alabama
Here's my thought, and it's only my thought.
At this point, not knowing what all they've dumped in the pool; If it were me, I'd ask them the completely drain and refill the pool with fresh water and not add any chemicals to it. I'd then pay them off and take over the chemical maintenance of the pool. That way you'll know exactly what is being added to your pool water.