Backyard Aquaponics
A place to discuss aquaponics

I'm having trouble with the water clarity in two separate tanks. I have two systems both 800 liter IBC fish tank with a custom grow beds approximately 36"x96"x12". They are in a greenhouse. Grow beds are about 4' off ground and tanks sit below them. Sump pump, pumps directly to the tanks and bell siphon flushes back into tank below it. Water used to be completely clear and know I can not get it back to the quality for nothing. Plants are extremely healthy and fish seam to be happy also. They are active and eating. The amount of feed that is put into the tank is usually consumed. I have added some azonite several months back but right after I put it in there the water seamed to clear up but was a little tea colored. But I could still see my fish. Now the water is tea colored and cloudy. S much that you can not see the fish at the bottom. Can anyone offer some suggestions as to what could be causing this issue.
Thanks

What is your water temp, I am not sure what kind of weather you are getting down there but up here it is still pretty cold. My friend and I were confused that my cycling system with no fish only filter pads all of the sudden went cloudy I had not bought a heater yet but the moment I warmed the water things were clear. Honestly no idea why this happened but could be something to look into.

I am too new at this to explain why, but when my water got cloudy last week I increased the flow rate to the growbeds. You could see the difference the next day and it's been clear since.

Whats your stock density, whats your feed rate and whats your pumping volume per hour?

Ok so the flow rate of the system now is about every 8 minutes the water cycles through. It's pretty fast but I can't slow it down are the siphon will not kick on. The air temperature did get in the 50's last night but it has been in the 70's during the day. And the night temperature hasn't really been that cool either. As for the density I can not see what is in the tank because it is too cloudy to see to the bottom but there is probably around 30 fish in 600 liters. The feed is usually all gone Gwen I finish feeding. This is a tank that used to never give me any trouble at all and the water used to stay crystal clear.

Just remove the Bell for couple of days (turns into constant flood) and watch the water clear up. I have given up on syphons as I find that it drags all the fines out of the GBs.

It depends what you are calling cloudy...

It could be fines in the water... but your water can have heap of fines suspended in it and still be clear.

If you are using siphons that draw from the very bottom of the GB then it will drag sediment from the bottom of the GB with every siphon cycle. I put the lowest slot in my gravel guard about 3/4" from the base and the same with the inlets in my bell... no problems with sediment being dragged from the GB.

If you mean cloudy as in the water has become opaque, or has a milky look to it, then this is a different issue.

Have you tested your Amm levels lately?

I am currently helping someone set up and fishless cycle a system. We put it all together about a week and a half ago and had it running fine. We then started adding urea every second day until we got the Amm to 0.5, the water was still crystal clear.

Then a couple of nights ago we decided to put extra bracing under the GB, but we had to drain the GB to do it. Initially we kept the pump and spray bar running in the FT, but the simple "half hour job" went pear shaped and we ended up having to stop the pump. We didn't get the pump and GB back on line until the next morning. In the mean time the water in the FT had gone opaque, or cloudy... For want of a better description it looked like someone had poured a cup of milk into the water.

Within a few hours of getting the pump and GB back on line the water cleared up and is crystal clear again... I believe it must have something to do with the Ammonia in the water and not enough oxygenation.

P.S. I've also seen water go cloudy when a dead fish has gone unseen in the system for a few days... again probably Ammonia related.

Just my thoughts.

This would fit with my situation...

After months of the siphon working properly and almost constantly, it has recently played up. First, my water went murky. I'm not sure if that came after the siphon playing up or not - I THINK it was before by a couple of days. Nitrates were high, higher than I have seen them darker than the highest level on my chart, but Ammonia etc were same as always, minimums. pH had dropped from 7.5 or so to 6.8 - 6.5.

I emptied the FT, removed the fish to an aerated bucket and cleaned out the FT - lots of fine black silt (and heavy couldn't just sweep it into suspension and have it exit the IBC with the water, I had to sweep it down to the drain) then refilled and put the fish back.

Next day it was murky again. I also played with the siphon a bit and it was back to normal working - maybe a little faster on the cycle than it used to be but barely noticeable. I cut the feed to about half amounts.

For 2 weeks or more the water stayed dirty green/muddy colour and I didn't see the fish except when they came up for food. Then the siphon stopped breaking, turning the system into almost constant flood - after running for maybe 15 mins the siphon will pause, then start again - the pause MIGHT be 30 seconds but no longer.

When it did that, the next day the water was crystal clear. It has stayed that way except when I have 'pumped' the siphon to try to get it to go back to proper cycles. Then the water under the inlet shows murky.

My guess - the gunk in the bottom of the GB is entering the FT and murking it up. When the siphon played up the system went constant flow and the flow rate is high enough that the water entering the siphon is NOT coming from the bottom of the GB, but flowing across the GB higher than where the gunk is. When the siphon works it is higher flow during the cycle and also drops the water level to about 2cms above the GB floor, easily into the gunk level.

Those stating they are getting mucky water because they run siphons are doing something wrong IMO. I've had a number of systems now... and sold and/or set-up dozens of systems... all siphoned... and I haven't seen an issue.

Here's an option for you. I fit a sink fitting/drain into my systems. Sink fittings sit flush with the floor of the GB. The sink fitting has an easily removed standpipe plugging it. This standpipe is about 5mm taller than the standpipe in my siphon and acts as a back-up overflow should the siphon ever block up (never happened yet). If you had one of these fitted then every few months you could run the GB as constant flood for a few hours, turn the pump off and let everything settle in the GB for a while, pull the drain standpipe and let a decent amount of water rapidly drain from the base of the GB (not into the FT), this would drag a fair bit of the suspended fines out of the system.

From what you are all saying about siphons dragging muck out of the GB's suggests CF is leaving all that muck in the GB... would your system not be better off running a siphoned GB followed by a swirl filter etc?

Yes, I think so Mr Damage. Certainly that's the plan for my new system.

I can't think of another explanation for my on/off murky water, particularly as, except for the high nitrates, my water quality is fine and both fish and plants are healthy as. And the nitrate rise would make sense also - dragging settled muck from the GB would also bring in unused nitrates.

Everything was just fine till a few weeks back - I had trouble seeing my fish but that was because the bottom of the FT was dark (no SLO) and I had plenty of algae on the walls (no light cover) but the catfish seemed to enjoy cruising that stuff. Then the siphon began to act up - the first few times when it didn't break I'd go pump it up and down a few times - twice this resulted in a sudden increase in water through the siphon and some leaves etc. on the FT surface, so I cleaned it out and it ran good for a couple more months.

Now it kind of breaks very briefly then keeps running. Pumping increases the suspendeds in the FT around the inlet, and letting it run as is clears the water beautifully.

If anyone can suggest something OTHER THAN the crap in the bottom of the GB being sucked in by the siphon when it works but being left in the GB under CF conditions, I'd be mightily interested.

As it is, I'm leaving it and spending my time on GH and new system. WITH filters.

I mention it because there is an ongoing debate here and elsewhere about siphons - some people don't like them with a passion, and what I am seeing, for exactly the reasons you give Mr D, seems to be a strong argument for having siphons. Might be different in a system that starts life as CF and never goes to siphon, but what I am getting suggests siphons do a better cleaning job of the GB.

I pulled out a fair few tomato plants a few weeks ago and added a bucket of gravel to raise the height in my bed. I didn't wash the gravel prior to putting it in. When I made my bed origianlly, I didn't wash it either, and after murkyness for a few days, the fines settled down and I had clear water. Well, this time it hasn't gone clear, so after reading this thread yesterday, I pulled the bell off my bed, and ran constant flood last night. Crstal Clear this morning. Will put the bell back on tonight and see if it stays clear, else will repeat and dump a bed load onto the garden.

Crystal Clear!!!

So Dr Bee, we begin to see some causation perhaps?

To me, it is enough - I was planning on filters for my larger system - now it is a must-do for me. If siphons can pull that much muck form the GB's I'd rather capture it BEFORE it gets in my GB's.

My beds have been running now for about 4 years the last 2 on F&D, I have pulled plants out and certainly does stir up the water (clarity & chemicals) but soon settles again. I intend to just keep running them on F&D until I have problems.
I use an el cheapo bilge pump to control on/off.
6mm hole hole in standpipe doesn't have enough drag to pull out fines. Then when GBs are full of water just acts like CF.

You've got a 6mm hole in the standpipe? What is that for and where on the standpipe do you have the hole? I'm presuming you don't have a siphon set up? Wouldn't the pump simply fill the GB until the water flows over the top of the stand pipe?

Or am I misunderstanding - are you saying your stand pipe is a 6mm tube?

6mm hole (sometimes two holes) in the base of the standpipe. This is how a flood and drain system (on timer) works.