If you tested the pH while the chlorine was in the orange range, it is invalid. An OTO kit like you have only gives valid pH results if the chlorine is no higher than 5ppm. Dilute a sample with half pool water and half distilled water and then run the pH test with that.

This chart can help you decipher those off the scale colors on the OTO test:> http://pool9.net/oto-chart/
But, do order a K2006 kit like I mentioned in the post above. You can't really get buy with only an OTO/Phenol Red kit like you have. It has its place for quick daily checks but can't be your only kit if you want to be able to maintain your chemistry properly. Test strips are horrible. The CYA test strip test is especially bad! So, who knows what your CYA level actually is. Order the kit.

What are the ingredients of the granular chlorine that you are using?

Until you can get the good kit and we know what your CYA reading is, I would just stick with bleach for your source of chlorine. If you are currently in the orange range, do not add any more chlorine. If you get too high, you risk bleaching out your liner. Just try and keep it in the dark yellow range for now until you get the good kit. (Do you sense that I want you to have that good kit?)

Run your pump 24/7 right now while you are working to clear the pool and clean the filter as needed. With your chlorine that high, I wouldn't think it would take long to clear this up. Killing the algae is the easy part. Clearing out dead algae in these little pools is a little more challenging but adding the sand filter will certainly help it clear faster!

Once you do get it clear, you'll want to always keep your chlorine in the proper range which is based on your CYA level. More about the CYA and chlorine relationship can be read here:> http://pool9.net/cl-cya/

However ------ I'm afraid the sand filter you bought is way too small for your pump. Your pool is approximately 7100 gallons. The 1hp pump is more than you need and pairing it with a small sand filter is not a good combo. What happens is that a too powerful pump will simply force debris through the sand bed without actually filtering anything out. This also sometimes breaks down the dead algae into even smaller pieces that are then even more difficult to filter. Plus, the force also can blow the sand out of your filter leaving you with a filter with inadequate sand levels to do the job.

I am not the pump/filter matchup expert here. I'm going to ask PoolDoc to offer his opinion on your pump/filter combo. Maybe you can return the small filter and choose a larger one since you haven't actually used it yet?

Hope this helps.

(Until you registration is completed, you won't be able to see the rest of the forum while you are logged in. So, copy that link and then paste it into a browser window after you log out.)