Mudslides into Pools!

Mudslide into Pool!
by Rob Cox, July 10, 2019

Image by Pool Services Network, Myles McMorrow
With heavy rains pelting all areas of the country this summer - it seems like strong rainstorms are the new normal. Along with over-filling the pool, and generally disrupting your water balance and consuming chlorine, very heavy rains can cause mudslides into pools, or just a lot of soils washing into the pool, turning your once blue pool into a very deep mud puddle.

When pools become saturated with solids from even a small mudslide, this can overwhelm your filter, and drastically affect water chemistry. How does one go about cleaning a pool that has been flooded, or had a mud slide or soils washing over the pool deck and into the pool? This is the topic of today's post - cleaning up a mudslide pool, or removing very silty dirt.

How's the Pool Area Drainage? 

Before I get into aftermath clean-up procedures for flooded pools, let's take a moment to think about the flow of water around your pool. In many parts of the country, the old 100-year Storm standard is now occurring more like every 10-years, and many planners and engineers are now using a 500-year Storm models in construction of buildings, highways and even pools.

A few years ago, I wrote the seminal article on Correcting Drainage Problems Around Swimming Pools, and these tenets still prove to be true today. A pool with a mudslide problem actually has a drainage problem. Normal rain storms, even moderately heavy rains will drain away from the pool quickly and completely, but for these very heavy rainstorms, your drainage system fails and water flows into the pool, instead of away from the pool.

So, take some time to consider modifications to how heavy rain is captured and channeled away from the pool. In some cases the problem is obvious, in others you may have to venture out with an umbrella, to locate the bottlenecks and overflows.

Mudslides into Swimming Pools

Image by Pool Services Network, Myles McMorrowIs it a big problem! When dirt, mulch and silt fills your pool, it also brings in lots of undesirable contaminants. Phosphates, bacteria, nitrates can all increase your chlorine demand and can lead to algae and unsanitary water conditions that could make your swimmers sick.

In addition, heavy dirt or mud elevates your TDS or total dissolved solids in the pool, making it more difficult for sanitizers and balancers to do their job most effectively. When the water is choked with solids, blue and clear water becomes more difficult to maintain.

If you can - draining, cleaning and refilling is a good option. But if you cannot or would rather not drain the entire pool, read on...

Cleaning a Mudslide Pool

1. Clean off the pool deck:

Use flat shovels, snow shovels or a garden hose and a push broom. Clean-up any debris, and dams and deltas that have formed around the pool deck, especially in any corners or areas where water is known to puddle or stand without draining properly.

2. Vacuum the pool to waste

You can make a Pool Porto-Vac with any old pool pump, a power cord and a few fittings, to allow you to place the pump next to the pool, connect a vacuum hose to the inlet and a backwash hose to the discharge, and vacuum to waste. Or if you have a multiport valve, you can just set the valve to the Drain to Waste setting, roll-out the backwash hose, and vacuum until the water reaches the bottom of the skimmer. Keep a hose running into the pool to replace the water being lost. Screw a hose adapter into the skimmer, and put the garden hose in the skimmer well, and you can usually continue vacuuming. You can also use our Pool Floc before vacuuming to waste, to help clump together and sink the suspended material.

3. Balance chemistry and Shock the pool

Once you get most of the solids from the floor of the pool, you want to check all of your water balance parameters (pH, Total Alkalinity and Calcium Hardness levels), and make any adjustments needed. Then shock the pool to oxidize contaminants and organic matter, and to disinfect the pool. Use regular cal hypo Pool Shock, or can use liquid chlorine if available, at a rate of 2 lbs per 10,000 gallons, or a double-dose treatment. Check that there is a good chlorine level 12-24 hours later, if not - repeat the shock treatment, until a strong (3-5 ppm) can be maintained for at least 24 hours.

4. Brush the pool (every day)

Brushing your pool will help to kick up the dust and get it into the filter, in addition to reducing the chance of staining, and helping to improve circulation. In short, it's good to brush the pool, every day until the water clears. Plus, it's good exercise for you! If your brush has seen better days, we have a great selection of pool brushes!

5. Add Clarifier and run filter 24/7

Use a good Pool Clarifier to assist in filtering the water, unless you already have a large and very effective pool filter. If your filter is tired or undersized, or if you hesitate to run the filter for 24/7 - then a Clarifier can provide a good assist to clearing the water faster. Clarifiers work as coagulants, collecting tiny particles into larger, more easily filtered clumps. Follow dosage instructions carefully and be careful not to over-dose the pool with clarifier, which can have an opposite effect! For small or weak pool filters, improve filtration with Jack's Magic Filter Fiber Stuff or by adding a Slime Bag to your return fitting.

Image by Pool Services Network, Myles McMorrow

6. Test for Phosphates

Phosphates are a tasty form of food for algae and other aquatic life, and they are to be avoided in pools. When a pool has a mudslide, or is filled with even small amounts of dirt and silt, very high levels of phosphates can cause water balance, water clarity and algae problems. You can test for pool phosphates with Phosphate Test Strips, or just treat the pool with PhosFree or SeaKlear Phosphate remover.

 7. Clean the Filter

After subjecting your pool filter to high volumes of dirt, silt or algae, a deep cleaning can be a good final step, to ensure that cellular matter and other micro contaminants are flushed fully out of the filter, and not left behind to reduce filter effectiveness or spur on future algae growth or cloudy water conditions. Pool Filter Cleaners are especially great for small sand filters or small cartridge filters, regular cleaning to remove calcium scale and oily deposits, can be the difference between water that is dull, and water that sparkles.

Thanks to Myles McMorrow of Pool Services Network in Mclean, Va for the pictures of a downpour of 6 inches of rain in about 2.5 hours, earlier this week.


- Rob