We know that the chemistry of the pool keeps the pool running properly but did you know that there is such thing as bad pool chemical combinations?! Well, we are here to help you wade through some of these combinations to help protect you and your pools health!
Welcome back students of pool, take a seat for our lecture today on bad pool chemical combinations.
We will start with several water balance scenarios that can result in unfortunate “side-effects’.
Then we will turn our attention to a few pool chemicals that should always be added separately, not together.
We’ll close with a brief discussion on best chemical safety practices, to prevent accidents from oxidants.
Let’s Dive-In, shall we?
Bad Water Balance Combinations
High pH + High Calcium: A recipe for scaling and cloudy water, forms scale film on pool surfaces and pipes, and can even form sharp crystallized nodules of calcium.
High pH + Low Chlorine: Perfect conditions for cloudy water and algae. Algae prefers a high pH level, and is just waiting for a low chlorine opportunity to bloom.
Low pH + Low Alkalinity: Will cause etching and corrosion to steel, copper, rubber, vinyl and plaster surfaces. Low pH is great for chlorine potency and algae prevention, but once it drops below neutral 7.0, acidic water begins to corrode pool surfaces and equipment.
Low pH + High Alkalinity: Same as above, only it becomes hard to raise pH, due to buffering effect of a high alkalinity. Add enough Dry Acid” to lower alkalinity (and pH). Requires several doses over many days, raising pH after each treatment.
Low Chlorine + Low Stabilizer: Hazy – cloudy – green is the usual progression. If you look at your pool everyday closely, you’ll know just by looking at it when chlorine is low. Act fast with pool shock to bring the level up fast, then fill your tablet floater or chlorinator. Outdoor pools should maintain a level of stabilizer in the 20-50 ppm range.
High Chlorine + High Stabilizer: This can damage soft and shiny surfaces over years of very high chlorine levels (5-10 ppm). High stabilizer levels over 100 ppm can cause problems in chlorine potency and chlorine testing becomes unreliable.
High Combined Chlorine: Chloramines are Free chlorine molecules joined with ammonia or nitrogen. No longer an active sanitizer, they cause red eyes and smelly pools. When chloramine level exceeds 0.3 ppm (TC-FC=CC), shock the pool.
Low Calcium Hardness: Creates a corrosive water condition, causing etching, and leaching of calcium from plaster or tile grout. Low hardness is also bad for vinyl liners when the water is too soft. It hinders overall water balance and chemical effectiveness, too.
High Phosphates: Phosphates enter the pool from many sources, but when a phosphate test exceeds 300 ppb (parts per billion), reduce them with SeaKlear or PhosFree. Phosphates and nitrates are favorite foods for algae, please don’t feed the animals. 🙂
Bad Pool Chemical Combinations
Chlorine shock + Algaecide: Chlorine shock will disrupt the polymer chains or chemical compounds used in many pool algaecides, and in most cases will completely destroy the algaecide. Use pool shock to kill algae, and save your algaecide until the chlorine level has returned to normal.
Chlorine shock + Sequester Agent: Chlorine shock will also disrupt stain & scale chemicals, aka chelators or sequestering agents, if added at the same time. Add Stain & Scale chemicals a day before or several days after, shocking a pool.
Clarifier + Clarifier: If you overdose a pool with Clarifier, a curious phenomenon can occur. Instead of behaving as a coagulant, the electron charge can reverse, causing some formulas to behave as a dispersant. Wait 5-7 days to treat again with clarifier, closely following dosage instructions.
Very High Cyanuric Acid: Have I told you the one about the guy who thought he was adding calcium to his pool but actually added 15 lbs of cyanuric acid? Also labeled Stabilizer or Conditioner, when cyanuric acid levels exceed 100 ppm, proper sanitation becomes difficult. The solution is dilution.
Chlorine Shock + High Metals: How about the guy whose copper heat exchanger was eroding from low pH, who shocked his poorly balanced pool water, and ended up with black streaks and stains? High metal levels can drop-out of solution in such cases. Keep pH, Alkalinity and Calcium Hardness within range, and add a regular treatment of a sequestering agent like Stain Away or Metal Free to keep metals in solution.
The Worst Pool Chemical Combination
Never allow pool chemicals to contact each other, even a drop of algaecide, clarifier, antifreeze, or other liquids mixed with chlorine, can erupt into a raging fire. Mixing chlorine and acid (pH down) creates a deadly gas. Mixing different chlorine types can explode when moisture is added. Chemical residue from a bucket or scoop mixing with another chemical can react. Dirt, dust, leaves and any liquid can cause a volatile reaction when mixed with pool chlorine.
Trust me when I say that chemical fires are extremely hazardous, as I have conducted many flammability experiments on our pool chemicals. Chlorine mixed with any other chemical or foreign substance can emit toxic gases, erupt in flames, explode, or all of the above.
Keep Pool Chemicals Clean, Closed, Dry and Separated.