newbie question about biologic filter with bio balls

[dutchstar]

Just getting ready to reopen my pond for our first spring at this house...aside from replacing the bulb in the UV filter and removing dead leaves (and a frog carcass) from one of the upper pools, I am looking at replacing the big grody lava rock-in-a-sack in the top pool with some bio balls. Pond is 3600 gallons and I have 7 decent sized koi. I live in southeast pa and water temp has been 48ish for the last week or so. Just took the netting off today.

Any thoughts/recommendations on this choice of filter media? And how do I figure out how much I need? One site says 80 balls per gallon but I think that's wrong...would have to take out a 2nd mortgage for the balls!

Any help is appreciated, thanks.

 

[Waterbug]

Any formula using gallons is a wild guess and has nothing to do with ammonia. Ammonia has everything to do with the amount of food you feed. But you'd also have to consider a bunch of other factors. So the only way to know how much filter you need is by measuring ammonia. There is absolutely no other way to tell, I mean and know. Anyone can guess.

You'll have time as the water will still be cool if you start to measure ammonia because the water will still be cool so the ammonia will not be toxic. Check ammonia temp pH toxicity. I would not be surprised if lava rock in a pool added hardly any filtering.

I like bio balls as submerged media because they have a better chance of not clogging with muck which renders them worthless. If you can get the media out of the water even by an inch with water flowing over them you can increase ammonia conversion by 10 to 30 times. Floating media under flowing water can also get those results. Kind of a fluidized bed. So you'd need a lot fewer bio balls.

 

[KenG]

When you're looking at the online sites and they say so many balls per gallon I think they're just telling you how many it would take to fill a gallon worth of space. And of course they come in different sizes so one may say 80 per gallon and the other may say 100 per gallon depending on the size of the balls.

 

[sissy]

With my bags of lava rock I always have some ready to go in when the others come out and I use several laundry bags full .I just soak them in peroxide to clean them .You can do the same with the bio balls too .Makes changing out easy and fast .When the bags start to fall apart I just keep some on hand from the dollar store .4 bags for a dollar .I don't always take them out as I have a small pump in the filter that I sometimes use that and do my water change at the same time ,flushes them nice and clean

 

[dutchstar]

Thanks for the input. I have a testing kit, and I plan to do the ammonia testing while the water is still cool.

The way my pond is set up, the water runs from the bottom end of the large pool, through a mechanical filter and the pump, up around the side of the pond through the UV filter and back up to the top of the waterfall. The top collecting pool of the waterfall is a trapezoidal vessel where there is a mesh bag with lava rock, as well as a few cut-to-shape mats of white filter material weighted down at the bottom with rocks. There is a ton of sediment, soil, and junk in there which i'll clean out before getting the pump running again.

After that, the water falls down to a second small collecting pool, and that's where i found the ex-frog. That is currently full of water (and dead frog) so i'm going to want to drain and clean that too before I start running that into the main pool where the koi are.

If I can get an idea of what I need in terms of quantity of filter media, I can order that stuff, along with a replacement UV bulb, and then i can get this party started again.

 

[Waterbug]

KenG, good point.

 

[dutchstar]

just did some testing, temp is now 51 (at 1300 on a sunny day but not in a sunny spot in the pond), pH reads 8.0 and Ammonia is 0 ppm

so it looks like i have some time to solve this problem. thanks for everyone's help.

 

[Waterbug]

Hard to get below 0 ppm.

Ammonia levels when you start feeding will tell the whole story.

 

[dutchstar]

Waterbug - agreed, i think zero is a good starting point.

Any input/opinion on the best brand/type of bioballs?

 

[HARO]

Dutchstar; KenG got it right, 80 bio-balls should fill a space of one gallon size, so if your filter has a five-gallon capacity, you would need 400 of them. Laguna has their own version, called Bio-Spheres, and Tetra has something similar, but in more of a cylinder shape. You should be able to find a few more on the internet.
John