High levels of nitrates.
No
what causes water hammer in pipe systems?
Nitrates are ionic compounds soluble in water.
a leak
When you sink in the pool, it is because your body is denser than the water. This causes you to displace water and sink below the surface.
Acid rain contains nitrates, as does some runoff water from fertilized soil.
Your incoming fill water may be hard.
In a word, Yes. Phosphates are really a non issue. Phosphates are an algae food but IF YOU ARE MAINTAINING PROPER FREE CHLORINE LEVELS for the CYA level in your pool they are a non issue and you will not get algae. Phosphates are also often not the limiting factor in algae growth. Nitrates are also algae food and the only way to remove nitrates from pool water is by water change. There is not a nitrate remover that a pool store can sell you so nitrates are not normally tested. Phosphate removers have become big business and big profits for pool stores and chemical distributors but they are an entirely unnecessary product 99% of the time if proper pool maintenance is followed. High phosphate water is perfectly safe to swim in.
Nitrates in water can come from fertilizers, sewage, and industrial waste. High levels of nitrates in water can lead to eutrophication, causing excessive algae growth that depletes oxygen levels and harms aquatic organisms. In drinking water, high nitrate levels can pose health risks, especially to infants, by interfering with the blood's ability to transport oxygen.
No nitrates are not needed.Mainly CO2 and water is needed
You should get the pool water tested for 'phosphates' and 'nitrates', both of which can encourage algae. Common problem these days. Easy to get rid of if too high (phosphates max. 125ppb, nitrates max. 25ppm). E-mail me if you need more help.