Swimming Pool

Is Your Swimming Pool Green? Phosphates May Be Your Problem


Many pool owners find themselves in a never ending struggle to get their swimming pool water clean and clear. DIY’ersget up early every Saturday to take a water sample to their local pool store. They do this in the hopes of being told the secret answers to maintaining their pools by whom I like to call, “the great and powerful OZ of swimming pools”. The man behind the curtain, well actually behind the counter, evaluates their water and tells them what to buy to fix it.

One week they are told they need shock, the next week they are told they need calcium, another week they are told they need to lower their PH level, etc., etc. Every week, it seems they need something different. And every week they dish out lots of money for the items they’ve been told will correct their pool water. Does this sound familiar?

Well, after 14 years of maintaining the same swimming pool at my home, I would like to share some information I have learned along the way. Please note, this information is only to be used as a guideline, which may or may not work in all scenarios:

Liquid chlorine is mostly salt. After years of using it, it greatly increases the solids in your pool water, making it more difficult to balance the water correctly. Stop using it is my recommendation. Switch to granular shock with an active chlorine level of at least 50%.

Phosphates act as algae food in a swimming pool. Reduce your phosphates to prevent algae growth.

Algaecides will kill algae, but they will not continue to prevent algae from returning.

Shock is a good way to correct your pool water and can actually be a replacement for liquid chlorine in your water maintenance routine. Use a 1 lb. bag of granular shock per week per 10,000 gallons. In the heat of the summer or during heavy use periods, you may have to increase the amount of shock you use.

1 cup of muriatic acid per week per 10,000 gallons will help keep your water looking crisp and clear.

1/2 cup of any quality phosphate remover per week per 10,000 gallons will prevent algae from appearing in your pool.

Whether you use any of the information above to alter your pool water maintenance routine or not, I urge you to ask the following questions the next time you take your pool water in for analysis:

Are the solids in my pool water within the acceptable levels?

Does my pool water have a high level of phosphates?

The answers to these two questions can be the information you’ve been needing to know all along. If you discover the pool has a high level of solids, it will be necessary to drain 12-18 inches of water from your pool in order to “flush out” and dilute the amount of solids in your pool. I am not aware of any other method of removing them. Again, build up of solids in the swimming pool make it much more difficult for the water to be balanced.

If you discover that you have a high level of phosphates, then you have a fairly easy way to correct that problem. Buy a quality Phosphate remove such as Natural Chemistry PhosFree or their new product Total. Add 1/2 cup, which is about a cap full, to your skimmer. This allows it to go directly into your filter where it will be trapped in your filter and thus allow it to “filter” the phosphates from the pool water as it flows through your filter.