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Discussion Starter · #1 ·
So I've had my diy 300 gallon up and running for almost a month (its progress has been posted in the diy section)
I'm attempting a fishless cycle but I can't seem to get the ammonia to stay in the water!
Ill explain...

About 10 days ago added enough ammonia to raise it to 1.0ppm. I tested 7 days later, and no ammonia! Well that was good I thought. Tested for nitrite: 0. Tested for nitrate: 0. I added more ammonia once again to 1.0ppm and tested the next day... 0! Everything read a very "for sure" 0! So I figured something must be wrong with my test kit, so I borrowed a very expensive digital monitor from a friend and tried it again...

Except this time I raised it to 2.0ppm. Tested a couple hours later with the digital monito... 0! Did it again, but tested one hour later.... 0!

So what gives? Does this ammonia "degas" more easily from the water? Or am I missing something very obvious when it comes to fishless cycles?

Filter is: huge wet dry/rapid sand filter plus algae scrubbers at the top of the tank, slightly oversized for the tank (not a bad thing just a bit bigger than the recommended minimum size).

Any help would be appreciated I wanna get this thing cycled so I can add fish darn it!

The fact that I never get nitrite or nitrate indicates there is no nitrogen cycle correct?

Thanks,

Lad
 

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Discussion Starter · #3 ·
Interesting... added ammonia to 1.0ppm a few minutes before my last post... only this time I unplugged the pump feeding the algae scrubbers.

1 hour later the digital monitor reads .21ppm...
Normal test kit indicates there may be some nitrate, but its a much much lighter shade of pink than the lightest shade on the color card... almost impossible to see...

So maybe I do have a nitrogen cycle but the algae absorbs the nitrates before I can detect them?
And the wet dry/rapid sand is just able to process the ammonia that quickly? Is it possible I have some bacteria consuming nitrates too?

Gonna try it at least 2 more times (once with scrubber running and once again with it off) just to be sure...

If that is the case, perhaps I can add fish now? (Well, I mean once the ammonia drops back to 0)

Oh forgot to mention... I do have some live plants in the tank too... ruled them out though because even on my heavily planted tank they don't use ammonia THAT quickly... I mean I know they help some, just not that fast...
 

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Discussion Starter · #4 ·
Prov356:

Haha... yep you think maybe they could process it that quickly? There's 2 small anubias and 5 tiny bunches of java fern
 

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The algae scrubber doesn't explain the rapid decrease in ammonia levels. I'd need full details on the system before commenting further. Seems you're trickling out important info. Is this like a quiz or riddle? Could be fun. :)
 

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Discussion Starter · #6 ·
Lol I'm sorry not trying to trickle info out... so here's all the details

Sump first:

Actual flow through sump is 1220gph (actually measured it, from a pump rated at 1500gph)

Water trickles first over a 4inch bed of sand, sitting horizontal and suspended above the water (not submerged). The bed of sand is 17inches x32inchesx4inches deep.

Water flows next through 3 vertical "columns" of sand each about 16x13 (about because they taper from 17 at the top down to 15.5 at the bottom) and each column is 4.5 inches thick.

All the sand is fine filter sand

Water then flows into the sump where the pumps and heaters are, as well as 4 bags of ceramic stars, just laying on the bottom of the sump.

Algae scrubber:

Actual flow to algae scrubber is 1055gph. 2 horizontal "trays" on either end of tank, each measure 16x26 inches. Lighting currently is 2 125w cfls on each tray, sitting about 3 inches from the surface...

Hahaha so hopefully I didn't forget anything!

Oh tank temp is 77...

Oh substrate is 1inch of large size filter sand
 

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How long's it been set up and running?

Did you use anything to seed the filters?

Sounds like an interesting design, how about some pics?

Normal test kit indicates there may be some nitrate, but its a much much lighter shade of pink than the lightest shade on the color card... almost impossible to see...
That's because you haven't added all that much ammonia yet. Based on your tests, I'd say you're cycled, but not enough info to say why. The filters would have had to have been seeded in some manner (possibly by the surfaces of the algae scrubber, or sand is from another system?). If it's handling 2ppm in 2 hours (both ammonia and nitrite converted) then that's a phenomenal rate, and you're cycled, whatever the reason.
 

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Discussion Starter · #8 ·
Oh very interesting. Yes seeded with some sand from my other tank, and a little algae I rubbed on the trays. Ill post pics a little later at work now... hahaha...

So the nitrates will build up more as a keep adding ammonia?
 

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So the nitrates will build up more as a keep adding ammonia?
Yes, ammonia is converted to nitrite, then converted to nitrate. I think you end up with about three times the nitrate as ammonia added. So, when you had only added 4ppm ammonia, your nitrates would have still been very low. I'd add 2-3ppm ammonia daily and keep testing. You'll know.
 
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