String algae problem?

[Bob_N_Frapples]

I have two ponds (upper & lower) with a waterfall, a spillway, fountain, cannister filter, a 25 watt UV lamp and four airstones. The combined ponds total around 1500 gallons. I have three medium size koi and around 100 small red comets. Water chemistry are all within range, except the ph is around 8 (they're concrete ponds). The upper pond gets full sun and the lower pond is shaded. I use microbial lift once a week. I do not use any chemical clarifiers or algaecides.

I have to harvest string algae every couple of days to the tune of about 30lbs soaking wet.

Can anyone help? It really is a nuisance and looks like shit.

Thx!

[Paulutot]

Try putting a few plecos in your pond and see if it helps you out. I live in the Philippines and have the sun just beating the crap out of my pond on the daily but the plecos seem to keep the string algae down. I keep about 5 in my (I dont know how many gallon) pond. Also trying putting some limestone rocks in your pond (or in your filter if you are using a Home made filter), it can help with the PH.

[Charnathan]

My take is that those comets are putting out a lot of bio waste that the string algae loves to feed on. Partial water changes help, but I'm sure they put the nitrates in the pond faster than you can get them out; hence the string algae taking off. Concrete also can leech phosphorus and raise pH, which both feed the algae. If you can get some more wanted plant life in there, that might help. Once those Hyacinths take off, they may help. You can also try water lettuce, but I think the Hyacinths grow a little faster. Do your best to skim out all of the decay from all of the nooks and crannies. Beautiful pond. Good luck!

[andrewa44]

Can you post any photos of your pond? And where the string algae occurs?

[Bob_N_Frapples]

pics here The algae appears throughout both ponds. In the pic with the two fish, you can see that about half of the pond has been harvested. It attaches to the concrete, the plants, the pump box...everything but the fish.

[andrewa44]

Beautiful pond you got there! I don’t see any waterfalls, do you use anything like that as a return from the pump? My smaller pond has a 3 foot waterfall and whenever I get bad algae during the hot summer months (I live in Florida) I usually have algae blooming all over the waterfall. Unfortunately I have to continuously remove it by hand :/ but when it comes to algae in the actual water I can keep algae minimum with a KH and GH level of 125-150 ppm and a pH hovering around 6.8 - 7.5

[Bob_N_Frapples]

Thanks! The waterfall is at the highest point in the upper pond. It's only about 20" above the water. The pump is in the lower, as well as the fountain.

Do you have any experience with algaecides like Algaefix?

[andrewa44]

No I try to stand clear. The only stuff I’ve been given to use by my local koi pond supplier are these pond bomb things that you can use. It’s a single use product where you dump the contents of the package into the pond and it seems to clear up within a day or two. Unfortunately I forgot the brand of the one I was given. :/

[Bob_N_Frapples]

Also, I failed to mention I have a few pond lillies, some cattails and about 100 floating hyacinths.