Use a filter cleaner, or change the sand or cartridge if it's not been done in many years. Use clarifier to help coagulate suspended particles or use flocculant to drop particles to the bottom. Fill the pool high with water and vacuum the pool to waste, by setting a multiport filter valve to waste (sand or DE filters).
If you shocked your pool water and it turned brown you probably have metals. Oxidized iron usually turns a brown or rusty color in the water. Use the No-Drain Metal Stain Eliminator Kit to reduce, sequester, and eliminate the metals to clear up your water and prevent recurrence or staining of your pool surface.
The fix for reddish-brown pool water is similar to the fix for greenish-blue water caused by high levels of copper. Add a metal control sequestering chemical into your water in accordance with the label directions, keep your pump/filter running and retest for metal content after 24 hours.
Brown-colored algae is actually a form of yellow or mustard algae, and not a separate strain of its own. The extremely rare mustard algae forms in pools with poor chemical balance and in shaded areas that get little sun.
Well maintained pool water can last up to 5, maybe even seven years before you need to replace it. This means weekly cleaning, functional filters, and checking ph levels every day.
Brush the walls every week during swimming season while the pump is turned off. A vacuum removes the debris that collects on the bottom. Vacuuming requires moving the vacuum head over the debris on the bottom of the pool until the bottom appears clean.
Depending on the type of surface in your pool, you can use a brush to scrap it clean with or without water in it. If the pool has a soft vinyl liner, you will use a rubber or nylon brush to keep it clean. If the pool has a concrete floor and walls, a stiff and course brush will do the trick.
If dirt is reappearing at the bottom of your swimming pool after you've vacuumed it your pool's filter may be working poorly. Pool filters often work poorly because they're in need of cleaning. If you have a sand filter for your pool you need to make sure that the sand is sharp and freshened up.
For extreme staining or serious algae blooms, plaster pools can be cleaned with an acid wash with muriatic acid, or the safer to use Acid Magic. Acid washing removes a thin layer of plaster, exposing bright white and unstained plaster underneath. Having your pool acid washed will remove most surface stains.
No, it's not safe to swim in a pool with metal stain. Barack James (author) from Green City in the Sun on April 11, 2020: Before adding chlorine, you need to be sure you are dealing with green algae and not copper metal stains.
Organic stains, like from foliage or vegetation, react to and are removed with granular chlorine. Metallic stains, like from hard water, are removed with granular Vitamin C. Rust stains reacts to dry acid, sodium bisulfate.
How much shock is needed to open a pool depends on the condition of the water. Our spring startup kits have 4 lbs of pool shock, but you may need more. For a clear but hazy pool, 1 lb. per 10,000 gallons is usually sufficient.
Shock your pool when you open it for the season to kill algae that has developed in the Spring. AFTER A PARTY OR HEAVY USE: People carry bacteria and chlorine levels can drop drastically when there are many active swimmers using a pool.
Calcium Hypochlorite: Also referred to as cal hypo, this chemical is one of the least costly and most convenient ways to shock your pool. It's usually sold in granular form. Needs to be dissolved before you add it to the pool. Must be used after dusk.
Recovering Pool Water
Adjust the pH levels as well as the water hardness. Use pool shock until the dark green water turns blue-grey. Make sure the filter is running throughout until the water becomes clear. Use a clarifier and flocculant to coagulate and drop particles to the bottom of the pool.
When to Replace the Pool Water
You should replace pool water every five to seven years. As much as possible, you should drain and refill your pool during mild weather. It's to avoid pool damage caused by direct sunlight and heat. Moreover, a pool maintenance company can recommend the ideal time to drain your pool.
I think the answer to your question is about 3-6 days. The problem is that the chlorine that you need to keep the bacteria in check is used up more quickly as the temperature rises, the activity increases, and as sweat and other body stuff is put into the pool.