Backyard Aquaponics
A place to discuss aquaponics

I have been having a huge production of slime. It requires cleaning of the 2 inch pipes exiting the filter tanks to grow bed due to flow restriction. If I don't clean the pipes for a day, the second day I'm garaunteed filter tank overflow. It's gotten to the point where it's too much to realistically deal with everyday.

The slime is clear and jelly like mixed with poo of coarse.

I have around 1-200 tilapia med to full size mix. There are 10 or so gold fish in the mix. Estsblished system of over 3 years.

System is about 1500 gallons with a 8 foot by 32 foot by 1 foot deep growbed.

Never had this much slime untill this year.

No it's not bio film found on the walls of the FTs.

This can't be normal. What should I be looking for?

Havnt checked water parameters in some 6 months since plants have been doing great.

What kind of filter is this and is it aerated or not?

can you take a picture ? or describe it better (colour greenish, brownish or really clear ?, long filaments or blobs)

FT -> RFF -> net Tank-> GB -> aerated sump

I'll do better than that, I'll give you a quick video clip on you tube. I'll work on it after work.

For now, the slime is long and seems to dissolve when agitated. It's clear. But can be brown when mixed with poop. If left to go into straight into grow bed, it will create a big puddle where the water enters the grow bed. Agitate the puddle and media a bit and puddle goes away. I stick a flexible pipe Dow the outlet pipe of net tank about 4 feet and blow air tons if this stuff comes out into the grow bed. I do this everyday to keep the pipe open or else the filter tsnks and fish tanks over flow from the restriction.

I'll see if I can include a pipe "blowout" cleaning in the video.

Wife ran a drop wise pH for me. She is said it was the lowest pH on the scale. 7.0. Havnt used the hanna pH meter in 6 months so it's soaking in water for now. I'll calibrate it when I get home then test pH again. Will probably need a new probe.

I look forward to seeing the video. Basically I'm looking to see where the conditions exist that are causing a particular organism to proliferate and I'm also interested in what those conditions are. The long and short of it is that if you change the conditions to favor some other organism then this problem will likely go away on it's own. My guess is that this problem is mostly after the net tank and probably isn't a problem between the RFF and the Net tank unless water is backing up from the net tank (which it probably is by now ). I'd probably use a static upflow filter after the RFF instead of the net tank (Dasboot's system is a good example of this). If you setup a static upflow filter or two you can use aeration to clean it so it's less hassle and less mess than the net tank. Looking back through your thread I noticed you had DO problems, have you solved these?

What are you feeding the tilapia? Depending on what the slime actually is this could be important. Many of these slimes are made up of polysaccharides so I'm thinking that reducing the input of sugars might help but I'm not sure of this.

One last thing - I haven't checked the filtration capacity of your system, I suspect in it's entirety it's OK but the location of this net filter probably means that it's not really adequate for the amount of fish waste you're trying to pass through it and at the very least you're stretching the limits. The RFF only catches the settleable solids, there are a lot of other solids for your net tank to take care of and process. It seems likely that the net tank is doing what it's supposed to but there's just to much waste so you have an overabundance of slime.

Scotty,

Yes, the slim problem is only between the net tank and and growbed.

DO: DO improved with the increase in water flow and the addition of the largest ebay air pump (looks like a big heat sink) with 6 air stones. No algae. Issue is the air stones get clogged as well and require monthly cleaning at least. Looking for a better solution to replace the air stones.

Feed: Wife will send me a link of the feed and I'll post up soon.

Bio filtration: I'm pretty sure the 4 foot wide by 32 foot long by 1 foot deep with pebbles is plenty. I have never had any (knock, knock) chemistry issues regardless of feed amount. Kids over feed sometimes...

Mechanical filtration: This I'm not so sure about. The RFF and net tank require FREQUENT cleaning. Should be daily but I honestly don't have time to do it daily so it's been more of a weekly to bi-weekly chore. Was thinking of building a RDF (dreaming). The net tank tank gets its water at the bottom and FLOWS UP thru the net and out the pipe to GB. Is this not an upflow filter. Dashboots thread is HUGE. Do you mind linking to the static upflow filter you refer too. I have plenty of 55 gallon barrels I could play with to help with filtration.

I have been wanting to add a DWC of the same size of my current GB to run parrallel to the media grow bed. I have not started that addition due to the lack of mechanical filtration.

Here is a link to the feed we currently use.

https://www.southernstates.com/catalog/ ... 40-lb.aspx

In a way but it's very difficult to clean since you have to remove the net and it encourages the bacteria to adhere to clumps of solids caught in the netting and to other clumps of bacteria. I could be wrong but I believe most of this adhesion involves the production of polysaccharides outside the bacterial cell, what you're observing as slime. The version of static upflow filter I'm thinking of uses more of a rounded media like K1 or K2 or in Dasboots case plastic bottle caps. Since these float they form a layer at the surface. This sort of filter works in several ways (interception, settling, trapping..) but basically the thickness of this layer and the size of the media used determines the particle size blocked. Think of the layer as a three dimensional sieve where the water flows up from below and out at the top. Because the particles are round aeration during the cleaning cycle causes them to tumble, releasing the trapped solids to where they can be flushed away through the drain. The filter is only aerated during the cleaning cycle, in normal operation you don't want to disturb the floating media because this would let solids through. If you set it up right the media level will go higher as the layer becomes plugged with solids - this indicates it's time to clean the filter.

Here is the page with the picture of Dasboot's (Andreas) static upflow filters - http://www.backyardaquaponics.com/forum/viewtopic.php?f=1&t=26487. They are quite simple and about all you can see here is the outflow in the center (blue PVC) and the media surrounding it. The water just flows up from below, through the caps and out the overflow. There is also a picture of my combination filter (green barrel) which uses the center for a static upflow (for solids filtration) and the outer portion is an aerated MBBR (for biofiltration). Mine works well but I wouldn't copy it, if you read the text you'll understand why.

On the food, I notice that is for pond use only and is a supplement not a complete feed. I didn't notice anything in particular about the feed that would generate any more slime than others but depending on how well this has worked I'd think about changing anyway.

Out of time for now but I hope this helps

Yup, lots of help. One more question though, how much K1 for the static upflow filter? Will be using a 55 gallong barrel...

THANK YOU!

Wish I could tell you for sure, partly it depends on how fine of particles you want to remove. More is not necessarily better because then it plugs faster and you have to drain it more often. Mine is packed about half full and I think Andreas said he used a 60 % fill rate but a thinner layer of K1 will do the same job as a thick layer of bottle caps. Probably somewhere in the 2 to 4 cubic ft (15 to 30 gallons worth) range would be enough but I really can't be certain. You don't want the media layer moving with the inflow that you have going into the barrel because this can cause channelization where the solids can bypass the filtration.

Note: The media will float higher initially but eventually will settle (probably will work a bit better after this).

FYI - Bottle caps are much cheaper but are apparently harder to agitate and clean with aeration (but still do-able).

Yup...was thinking 4 cu ft. I see Ebay has different brands of the "k1". are they all the same? or any brands to stay away from.

Working on the slime video. Should be up by morning with the slowness of youtube upload etc...

right now I siphon the RFF which can be nasty when getting a mouth full lol. Would two static up flows be better than a RFF and 1 static up flow?

pH 6.0 (according to the HANNA pH meter after 6 months of no use but calibrated)

This is who I purchased from the last time - http://www.ebay.com/itm/Kaldnes-K1-K2-K3-Bio-Filter-Media-56-63-Liter-or-2-Cubic-Feet-/221298358461

I got 2 cubic ft of the K2 (5 spoked media) which has a slightly higher carrying capacity according to the info on ebay. Your not using it for an MBBR but it might still come in handy somewhere down the road and there is some waste processing going on in these filters even though they are primarily viewed as a solids filter.



I think they'd be about equal but the RFF might have an edge when maintenance and cleaning is sporadic. Since you already have the RFF, if it works well, I'd keep it and just add one static upflow filter.