Pea Gravel Media Problems

[William Sherman]

I was setting up a new system and went to a local nursery and purchased a trailer load of pea gravel.  The gravel really looked good, a mix ranging from 1/4" down to almost sand sized.  My wife and I washed the gravel until the water turned clear and proceeded to put it in our grow beds (GB).  We have a 250 gal food grade liquid shipping contain which I sunk into the ground, as a Fish Tank (FT).

We filled the tank with well water (ph 6.8) and added  aeration and fish.  We saw algae growing and felt we were home free.  We started circulating through our GB and suddenly we had the "red river" in our FT.  We couldn't see anything in the tank, so we drained it and got the fish out into clean water.  I got in and power washed the FT and started with new water.  My wife and I once again washed our gravel, 1 cup at a time and we started out again with clean GBs.  We also purchased a 5-way tester and began daily ph testing.  Mind you, we started with well water with a ph of 6.8.  Upon starting to circulate through the GB, we saw our ph start climbing.  We tried adding vinegar and ph-down, but nothing would get it back in range.  Shortly thereafter our fish started dying off and we finally lost them all.  Our FT remained pretty clear (a little cloudy, but could still see the bottom).  We are currently in a holding pattern, no fish and no plants in the GB.

We are pondering our next step.  We are considering doing another wash of the pea gravel to include a soak in pool acid before the final rinse to hopefully neutralize what ever is leaching out of the pebbles.  Has anyone out there encountered a problem like this and do you have any recommendations?

Frustrated in East Texas

[TCLynx]

Study up on fishless cycling would be my recommendation. It is far less stressful than cycling with fish in a system, especially with your high pH well water. (You want to avoid raising pH when there is high ammonia and fish in a system and an ammonia spike when cycling with fish is generally inevitable.) And doing a water change is often recommended but if your well water will only raise pH, it isn't a good thing.

So, here is a link to a thread I started about fishless cycling on the BYAP forum (I'm not up to repeating it all at the moment)
http://backyardaquaponics.com/forum/viewtopic.php?f=11&t=6809

[Nate Storey]

TC is right. if you have a pH spike with high ammonia/ammonium your ammonium (NH4+, predominant species at low pH) is converted to ammonia (NH3, unionized=very very bad). NH4+ is still not good, but doesn't diffuse across your fishes' gill membranes or through plant tissues nearly as readily as NH3, which has no charge. I've got a cool graph i made a while back plotting nutrient availability (of interest to plant production) versus nitrification activity and NH3/NH4 species predominance (of interest to your fish). . . I'll go look for it.

TCLynx said:

Study up on fishless cycling would be my recommendation. It is far less stressful than cycling with fish in a system, especially with your high pH well water. (You want to avoid raising pH when there is high ammonia and fish in a system and an ammonia spike when cycling with fish is generally inevitable.) And doing a water change is often recommended but if your well water will only raise pH, it isn't a good thing.

So, here is a link to a thread I started about fishless cycling on the BYAP forum (I'm not up to repeating it all at the moment)
http://backyardaquaponics.com/forum/viewtopic.php?f=11&t=6809

[William Sherman]

TC,

Thanks for all your help. Went to BYAP and found whole "new you". You're a busy "APer". Hopefully you or someone else with experience can steer me in the right direction. I'm starting out completely new and according to the "fish-less cycling" I need to dose my system to achieve a 1-2 ppm of ammonia. With say a 300 gal tank and ammonia that says it is a solution of 10% Ammonium Hydroxide, approximately how many oz. would I need to start with? Incidentally, finally found the Ammonia at ACE Hardware.

Thanks,

Bill

TCLynx said:

Study up on fishless cycling would be my recommendation. It is far less stressful than cycling with fish in a system, especially with your high pH well water. (You want to avoid raising pH when there is high ammonia and fish in a system and an ammonia spike when cycling with fish is generally inevitable.) And doing a water change is often recommended but if your well water will only raise pH, it isn't a good thing.

So, here is a link to a thread I started about fishless cycling on the BYAP forum (I'm not up to repeating it all at the moment)
http://backyardaquaponics.com/forum/viewtopic.php?f=11&t=6809

[TCLynx]

I'm not sure how much commercial ammonia to use. I've always use the free humonia kind. For a 300 gallon tank I might start with 300-500 ml of bottled aged pee. If it is fresh, ya gotta wait several days before you can expect to see an ammonia reading.

[k edmonds]

Gravels can vary all across the country. In my years working with golf courses we were endlessly testing the physical properties of different gravels and sands so they would work in an USGA spec'd golf green or tee. Sometimes the correct gravel would not be available and it would have to be trucked in. Angular sand and gravels were always favored over rounded. You end up with more surface area with angular. This does a couple of things. First when trying to establish the bacteria population there are more places for them to hang out. Second, and I am not sure if this completely applies to AP, but angular will fit together without compacting and allow water to flow through without being restricted.

Most states building and road departments dictate what size and type of gravel can go into concrete and asphalt and hence this dictates what is available for the rest of us. 1/2-3/4" gravel should be a common gradation anywhere you go. This does not mean the chemical composition would be ideal in an AP system. I am using a 1/2-3/4" gravel that is inert. I paid approximately $22/ton from a secondary supplier. Going to the sand/gravel plant would have saved maybe $5-6 per ton.

TCLynx said:

I guess I hadn't paid very close attention to size on the gravel. My gravel is 1/2" brown river rock, which means it fit through the 1/2" mesh screen when they separate the gravel into different products. So my gravel is 1/2" and smaller. It seems like fine media to me but I have a good population of composting worms. I think a mix between 1/2" and 3/4" would be even better but I've never found that size mix in an affordable option that wasn't limestone.

I personally think 1/4" and smaller may well give you some issues long term.

[Ethan Mills]

Hey, this might be an interesting video for you to watch. It is how I set up a bell siphon and a cheap and easy aquaponics system, theres a step by step guide to aquaponics linked on the video:

http://www.youtube.com/watch?v=T1iT6SozgZA