Just after we had worked to get a beautiful 20-22" pea green bloom, we had taken the fertilizer bags out, and then....
The farmer uphill fertilized his hay fields, it rained for three days and the bloom is currently at 14". It's been cloudy and hot and we're getting worried about the possibility of an O2 kill.
Is there anything we can do?
We've had half of the diffusers off to help get the bloom established. Would turning the remaining half on help reduce the bloom or would that mix up to much unoxygenated water?
Any advice at all?
-Scott & JB

If you can't get your hands on one or more surface aerators I would rent a trash pump from your local rental supply and rig it to pump your suface water out onto the surface of the pond. You want to create as much spray and suface distrubance as possible. Diffusers are not really good at adding oxygen in emergency situations. Night time is when you should worry the most. From the literature I have seen 12 inches or less is the time to worry but it. Doesn't hurt to do something just in case you are headed for an algae crash.

Be Prepared if the bloom gets denser or if the water quickly clears. DO crash emminent. Lowest DO will occur just before dawn.

In the short-term, is there a way to reduce the bloom safely?

Cecil's advice is the best for the short term situation. Surface aeration is the cure for what ails you. You probably won't have a DO problem until your visibility gets down to less than 12" but be ready before this happens. I had this happen to me on a 1.1 ac pond in south Louisiana that has 5 acres of runoff into it. The danger is when the bloom gets dense and then you get 1-2 days with heavy cloud coverage. You won't know what hit you. I now have a 3/4 hp surface aerator in place with a timer set from 4-8 AM during the hot summer months. For immediate relief a 2" jagger/trash pump choked down to a 1" discharge against solid or slat wood surface before it falls into the pond will create some 0xygen. Time to start shopping for a surface aerator. Mine was about $800. It is 220 v and hopefully will last many years.

I just checked again and the bloom is at 12" and in some places there is about .5cm thick lime green slime where there is a 13-14" bloom underneath.
How many surface splashers or trash pumps would it take to save 8 acres from an 02 kill?

jbrockey, You may want to find out what fert was put on as is common to fertilize hay (alfalfa) with straight potash 0-0-60 or 0-14-42 or similar.Often Boron is used in these mixes which you would know in a hurry if boron gets in the water. In my 25 years in Ag I never had a problem with "hay" fertilizer" moving Usually a low to no "N" is used as alfalfa fixes its own "N"and phosphorus is for the most part immobile so will attatch to the clay in the field which is the reason it is used little in hay production (it wont move to the root system) Alfalfa roots are often several feet deep.If it was a grass mix stand still very little "N" was probably used so you may not experience the problem you are preparing for. Just my .02Cents, Hope it works out !! Ted

Sorry I couldn't respond sooner, had to earn my keep. If you haven't gotten a pump yet and still have a "bloom" problem, here is a suggestion. On 8 acres I would first turn on all of my diffusers. Then I wound get 2 - 4" jagger pumps and put one on each end of the pond. I would choke down the discharge to 1" and shoot it at the surface on a flat angle or shoot it against a splash board if I could. These pumps move 650 gpm, but you may have to run it slower with the backpressure caused by necking down the discharge. Please let me know how things are going?

Why turn off the diffusers?

I didn't say off, I said On!

Oh oops my bad. I must have read that 10 times and was sure it said "off", I dont know how I did that. Well the situation is improving anyway. The bloom has somewhat shifted to a brownish zooplankton shade and faded down to about 24". We may actually start up our fertilization program again soon.
thanks for the help
-Scott

No problem, I,ve had the same problem on occasion!! When you start fertilizing again go slowly and try to find that happy balance! Remember to watch for the high temperatures coming to your area soon, they,ve been here for a month now. We are fighting the rains and cloudy high temp days for about three weeks. Without our aerator we would be in big trouble again! Good luck with yours!!