Pond Boss Forums MANAGING AN EXISTING POND Fertilization Maybe I should drain, dry, and refertilize?

I messed up with my bluegill production pond this year. I should have drained it just before I refilled it and fertilized it to prevent any macrophytes from getting started robbing nutrients needed for the algae bloom.

Anyway I have gin clear water with macrophytes on the bottom. :-( Even with weekly fertilization the water stays gin clear so apparently the macrophytes are using up all the nutrients. No problem with low alkalinity here as the alkalinity is well over 300 ppm.

So the question is what should I do? Accept that bluegill survival may be really low this year hence fewer fish, or drain, remove the broodfish, and let the pond dry a few days to kill macrophytes, and then refill, restock with broodfish, and fertilize again to get an algae bloom going.

One thing in my favor for the latter option is I did not get reproduction until July last year and I am only seeing on and off bedding. And I'm pretty sure I would get a second spawn even if there was already one.

Thoughts?

How many YOY do you want, Cecil?

If not very many, consider them already culled for aggressiveness.

I'd like to have a good number to cull the fastest growers from. However I'm concerned they could overeat what little zooplankton there is and all could go bust. I know a perch producer who had that happen. Didn't harvest a single perch!

I'm going to drain and start over. It will only take a day to drain it with the trash pump (100,000 gallons). I asked a list serve of fish producers and so far it's unanimous that they would drain and start over.

Cecil,

What kind of fertilizer and application rates were you using? How big is the pond?

Alk of 300ppm is way up there. If im not mistaken doesn't a high Alk sometimes cause for it to be harder to start a bloom.

I think I had an Alk of 140. Dropped in 2 gallons of 11-37-0 and 100lbs of Cottonseed meal per acre, and still didn't get a bloom untill the second application a month later.

Just a thought I may be wrong.

Alfalfa meal once a week supplemented with 10-34-0 liquid fertilizer. The 0 is not really zero. The farmer I bought it from couldn't remember how much he added.

The pond is only 1/10th acre and I was applying 20 lbs. per week of the alfalfa meal and 1 lb. dilluted in water of the liquid fertilizer. This worked for me last year.



Could be, although I was always under the impression that low alkalinity was usually the problem.

Just my luck. I see a lot of bluegill fry on the day I start draining the pond. I'm going to see if there is anyway I can salvage them before I completely drain down.

The consensus among all the aquaculture specialists I queried is to start over and do it the right way for all my effort. So that is what I am doing.

Update:

The bluegill production pond is coming down and it's obvious I have been fertilizing macrophytes and Chara (submergent vegetation) instead of phytoplankton!

Chalk this one for experience, and if I get a second hatch after I drain, lime, dry, refill, restock broodfish, and refertilize I will be happy!

How could I have been so dumb!

Wait don't answer that.

cecil too late now I guess but why not apply herbicide to kill macrophytes? Let us know if you wish to have bag of water soluble fertiliezer easeir to use and easier to tweak bloom since it goes right into solution.

I'm gonna answer it anyone, Cecil.

My FIL always said that if you don't do anything, you never make any mistakes. You do plenty (and are entitled to the relatively few mistakes that occur).

The herbicide of choice for the Potomogen pusillus and what I have in storage (Hydrothol 191) may have killed the fish too and sure would have killed the fry. I did try Cutrine Plus on the Chara (didn't know I had Pondweed in the pond at the time) and it was not effective at all. Apparently the hardness of my water (almost off the charts) makes it less effective even on filamentous algae and new growth Chara. The granular does absolutely nothing!

As far as the fertilizer thanks for the offer Greg but I've got a liquid I will apply along with alfalfa meal. if I didn't have this already I would consider your offer. Thanks!

That's what I keep trying to tell myself.

Here's some pics of what was growing on the bottom and sucking up nutrients vs. the phytoplankton. First pic is of some Potomogeton pussilus (Small pondweed) with some filamentous algae, and in the second picture filamentous algae is covering up the Chara.





Here is an overview of the bluegill production pond. I should have it completely drained tomorrow. 4 days of drying and I will refill.

Cecil:

In this weather you think it'll take 4 days? I'm losing almost 2"/day in this weather.

Are you sure that's evaporation? I've never lost that much that fast. In fact I will be lucky if I get all the water out even with the pumping I am doing.

Well, technically, yes it's evaporation, BUT not just from the pond.

The surrounding woods/soil that was standing water is going down fast as well, and I'm sure some (well, maybe aLOT) of water is leaving the pond via the sandy soil to make up the difference. Before I renovated the pond last year I would have up to 4' of water leave the pond from Spring to Fall. Some BG are on the beds in shallow water, and if they look like they'll get in really shallow water I might start dumping in water from the well.

We ran into clay in the renovation, but not enough to make a liner. So, I'll just see what the water level does this year. @ 28 gpm, I don't know if the well will do much good in a 1 1/2 or so acre pond.

Cecil, I'm not sure you will rid of the weeds by just leaving it dry for 4 days. I recommedn reward appliation in addition to the draining. It will only take a little (pint-quart)then you will have the remainder for future use.

I'm sure you're right Greg as you have a lot more experience than I do. But business is so slow due to the economy I can't afford anything other than a little hydrated lime I used to kill any left over predacious insects and some alfalfa meal to add in addition to liquid fertilizer I'm adding. (Actually the wife paid for it!) However I was told by my former perch producer that if I get the pond drained and go down and turn the weeds to thoroughly dry them I should be O.K. I ended up drying longer than 4 days too. I hoping if I get a good bloom going it will impede the macrophytes?

The pond is now filling back up and should be full in couple of days.

The several hundred fry I salvaged seem to be doing good in the 6 foot diameter circular tank I have them in. They are coming up to eat the fine powdered freeze dried krill I am feeding them. I also have about 3 gallons a minute of gravity feed flow going into the tank from a pond above that should be adding some zooplankton. It also does a good job of flushing out wastes.

Cecil, I have some really small ponds that dry up in the summer. They stay dry for a couple of months. However, when it rains the salad comes back in a hurry.

I have no doubt about that. However did you fertilize right away to get a phytoplankton bloom going?

I have some Hydrothol 191 I could add that would keep the weeds at bay but it can also be lethal to fish especially fry.

I'm just going to hope to get a phytoplankton bloom going fast enough to keep the macrophytes down.

These are too small to fertilize and I never had to.

The feral hogs haven't even been able to muddy the water enough to keep the weeds down.

Pond has been drained, dried, refilled, and fertilized with both alfalfa meal and liquid fertilizer. Now once the water warms up another 5 degrees (filled with cold trout pond water) I will move 5 females and at least 5 males to the pond. I don't want to aclimate them. I just want to move them and be over with it. The ponds are only about 10 feet apart. Hopefully I will get a second spawn. I do have about 500 fry in a tank I will add to the same pond once I get my 5D000 and 5D001 Aquamax. Right now I am feeding them ground up krill.


I just found out something I may have been doing wrong. I found a more precise publication for fertilizing fry ponds:


http://www.ag.auburn.edu/fish/AQUANIC/documents/SRAC469fs.pdf


that helps you calculate how much liquid fertilizer based on calcium hardness. Before I was using a rough estimate not based on water chemistry. According to this publication it's two gallons per acre at 50 mg/l and an additional 1 gallon per acre for each 75 mg/l calcium hardness. Dilute this at least 10:1. So if I go by this publication I've been adding only 1/3 of the liquid fertilizer I should have added. Says if not enough is added the calcium can inhibit uptake of phosphorous. That could explain at least in part why the macrophytes took hold before I got an algae bloom.

Hey I'm learning!

Wow what a difference! Within two days the pond is a nice rich green color and water clarity is 37 inches with a seechi dish! I will keep monitoring clarity daily and adjust accordingly. It should only get better. A lot of sunny days on tap the rest of next week.

I caught one female bulging with eggs in the pond next to this one and moved her (Only 8 to 10 feet seperate the ponds). Hopefully at feeding time this evening I will get several more brood fish moved.

Gonna move the several hundred fry back into this pond any day now.

Well, we all learn with you Cecil...

Not sure I agree with everything in the SRAC pub. The key is monitoring I feel, wait two weeks if not add desired level fertilize again. Every pond is diff so do not go by a certain the rules change with your pond just do it slowly in the heat. ALso Cecil one of the most important things to consider with using liquid fertilizer is diluation the more dilute you get it the more likely it is to be "taken up" in the water column and not be bound in bottom sediment.

I agree with Greg. Cecil there is no substitute for experience with a pond. Go slow. For example in one of our ponds I have never put more than 30% of the recommended amount of fertilizer and it can still go from 30 inch visibility to under 12 in a couple of days. Not what you want in 100 F temps with little rain.