TCLyx system combo just grew and grew.

[TCLynx]

My Big system started out as a basic simple flood and drain media bed system with the fish tank in ground and the beds above with a constant pump and autosiphons draining the beds back to the fish tank.  I got it up to the 1:1 grow bed volume to fish tank volume and then it just kept growing and changing.

I added NFT pipes as my first hybrid add on.  I did tinker with some rafts on the sump tank at one point but they didn't work so well for various reasons.  Later I got some of Nates Towers and now I'm in the process of adding a large DWC raft bed.

My filtration needs are amply taken care of by my gravel beds, however, I do need to use up more of the nitrates though more of the year so the raft bed might be a good way to grow more plants faster.  Either that or see if my ducks will eat duckweed grown in that bed if the rafts don't work for me.

[TCLynx]

Currently I have about 700 gallons of main fish tank and over 1400 gallons of media beds

There is an additional 100 (usually filled to about 75) gallon fingerling tank attached to the system as well as a 300 gallon sump tank. No fish in the sump tank. All water going to the sump tank has gone through gravel beds after the fish so it's what I call a clean water sump.

There are about 35 feet of NFT pipes being fed the filtered water from the sump tank.

There is grow space provided by Zipgrow towers though they are being fed filtered water from the sump tank and so are not really providing any solids filtration and were not needed from a bio-filtration point of view.

The raft bed is not online yet really so I'm not counting it but I expect that bed will hold a bit over 500 gallons of water.

If I measure ammonia levels on the water as it exits the fish tank, I can usually just barely detect a trace of ammonia but by guessing at what half of 0.25 ppm would be I would say the trace of ammonia is below 0.10. If I measure the ammonia levels of the water in the sump tank, they are 0. Only time I've measured nitrite in this system was when I have had it way overloaded and was still feeding heavily. (Might not seem like much to have over 100 fish in a 700 gallon tank but it is quite another thing when many of those fish are over 3 or even 5 pounds.) Anyway, I'm thinking 70 fish growing out big would be more appropriate for this tank and even then, I'm really pushing things. If anything went wrong.......

My nutrient levels in this system have always tended to stay quite high. Part of it is my system pH due to shells as media I think. pH buffers to 7.7 but when feeding is heavy I can some times see it down at 7.2 now days but still. many plants don't seem to make as efficient use of the nutrients and the nitrate levels stay quite high for me. I'm hoping to see if the raft beds will use up those nutrients faster despite the higher pH.

I'm not sure if this really answers your question, I'm not quite sure how to figure the ratios for the non gravel beds. I've always gone with the volume to volume to make sure I get enough solids filtration for my heavy stocking. I'm hoping that as my other system matures I will be able to see how a lower pH affects the nutrient levels in a flood and drain media system with deep beds.

[Harold Sukhbir]

TC you are truly the mixed AP master on this site by virtue of your ever expanding system. With the recent addition of rafts, can you update what's happening with your readings now or is it still too early? You also mentioned that high nutrient relates to PH,very interesting. I started with a no-name brand(bulk feed) from china and never registered any nitrates, then i switched to a higher quality feed and the levels are slowly rising,plant growth increasing, although i suspect it's because the system is still young and therefore still cycling. I've learnt that you can have the best water parameters but with poor feed your results will be diminished.

[TCLynx]

Yes Harold, high quality feed will make a really big difference.

 

As to my system and the rafts.  They are not online with the main system yet.  When I got the new pond liner I was nervous that it might not be fish safe even though being sold as "pond liner" so I kept it separate with some test pilot fish added to see if they would survive.  Now with the cold it could be a while before I see if the bio-filter can establish in the raft tank.

 

I still count myself as a media based Aquapon.  I have never run a system without media beds.  I don't know that I would really feel that I'm a master at anything else until I actually set up and completely cycle and harvest some fish and plants from a system run by other means before I would claim solid experience of the other methods.  Till that point, I still feel that the NFT pipes, towers, rafts and whatnot are all just add-ons to a media bed system.  As in the media beds are the filtration and the basis or backbone of the system.

 

As to the pH and nutrient levels.  I expect that my plants with the high pH have more trouble taking up nutrients (since some things are locked out at the higher pH, those other things will be limiting and not all the nitrates get taken up.)  I'm hoping that my 300 gallon system which is running a lower pH will prove me on this by running a lower nitrate level as it matures.  Will have to wait a bit on this one since it's now cold and everything will be a bit slow for the next couple months.

 

I am hoping that with the addition of the raft bed on my big system (I expect it will be online and functioning some time after the cold season) that I will manage to use up more of the nitrates from the big system water by growing lots of lettuce and such.

 

Will see, all will be slow for a while now.

[Harold Sukhbir]

I am always amazed that you run above the standard target of  7 PH and get the kind of results i see from your pics.Some AP'ers suggest an ideal between 6.5 and 6. Your constant buffering also add high calcium which is great for plant to human,makes me wonder if it's a better idea to use a high PH water source and utilize buffers(shell media), as maturing AP systems will demand this eventually. I too view media as the central component in mixed AP, as it is the simple and only truly definitive way to solids processing/nutrient conversion.

[TCLynx]

Well, I would suggest that most people should be running a pH above 6.5 because those who run at 6 with the standard API test kit can't actually know if there pH might actually crash way below that so it is kinda dangerous.

 

As to the higher pH.  That big system, I didn't know better and used shells as about 40% of my media and so the system is strongly buffered.  I don't really recommend it unless you really just want to grow water cress.

 

Yes as a system matures you need to add buffer material.  The really unfortunate thing is there are no self regulating buffers that tend to a pH of 6.8 which would be perfect.

 

The shells tend to a pH of 7.6 which is great for the bio-filter and fish and will still work for many plants but will require iron supplementation and some plants still will struggle.

 

Many things work, what you do should be balanced by the goals and the situation.