Hi! I'm visiting my mother in North Carolina. She has recently moved to a property that has a pond about 700 square feet. It has a small creek flowing into it and a small creek flowing out of it. We measured the best we could and in the in flow equals the out flow. Its not in full sun but does get a bit of sunlight on it. It has came pre-stocked with rainbow trout about (50). It has been getting more and more alage on top and the water is getting a bit merky. What would you suggest we do? Add a bottom aerator? Adding more diversity to the water - fish? plants?

Thanks!

Welcome to the forum. I'd think about starting to take out the RBT as they will usually die if the water gets warmer than 70°F.

The FA in the pond is due to excessive nutrients. With a flow thru system like the pond, unless you can somehow reduce the amounts of nutrients in the creek, I doubt that you'll have much luck reducing the amount of FA.

Check to see if Tilapia are legal to stock in your state. If they are, I'd look at stocking some - they eat FA. Be careful with the water temps. Depending on the species of Tilapia, they might not do well in water temps below the lower 60's.

There are very safe effective treatments that can be successful. I'm guessing this Creek is fairly cold and if the trout have been surviving then I wouldn't get crazy changing put fish quite yet. Take a comprehensive look at the big picture with your pond.

If this pond is essentially a wide spot in a year-round, flowing creek, the state may need to be asked if Tilapia could be stocked. If the water is cold enough to support trout, or is spring fed, Tilapia will not be a great option at all.

What would some of the "effective" treatments be in a pond with constant flow? Any chemicals will be flushed out and kept diluted, and fresh nutrient is constantly introduced.

The ONLY safe and effective treatment I would consider is had by calling Applied Polymer Systems, sending them a water sample to be analyzed along with your desired goals, and they will give you a special blended "log" to put into the inflowing water. It dissolves and binds up the phosphorus needed to take away an essential algae producing nutrient. The logs are not exactly cheap, dissolve in about a months, and require several logs, in stages, to work well.

Surface algae can be related to unbalanced levels of nutrients in the water. Is your mother using any fertilizers in the surrounding area?

This can also come from overfeeding fish -- is she is in fact feeding them.

Hop this helped!

My best guess. Here is the problem you may be facing. Housing in rural and many suburban area's mostly have septic systems plus farm fertilized field that eventually run into streams and rivers causing high nitrates in the water. Slowing this water into a quiet area with summer heat would allow algae to form with all of that fertilizer in it. It would seem most fixes would be washed right out of the pond.

On the other hand a couple of guy's I know with dammed ponds have flow through streams and they control their FA algae with copper sulfate that is pretty cheap in price. Or growing excessive amounts of aquatic plants would help.

Hi franker! Please share images of the pond to have a look.
Have you done water test of the pond?

There may be imbalance in pond water ecosystem or it has high nutrient levels.

There are some products that are effective, Removed unauthorized advertising link to remove algae and hydra silt-less to clean sludge that make pond look murky.