Fishless Cycle: This Seems Odd...

[Autonerd]

Hi all -- I'm about 20 days into my fishless cycle. My tank had been reliably dropping from 4 ppm ammonia in 12-15 hours. Nitrite is at 0 after 24 hours and accelerating. Buuut, in my last couple of tests, ammonia has been creeping up to 0.25 and even 0.50, even with nitrite at 0. Nitrate has been holding steady at about 40 for the last 3 days.

I did add some plants back in in the last couple of days, but some had started to die and have shed some brown bits. Could that be increasing my ammonia? Or is something else going on?

Incidentally I pulled out the dying plants, trimmed the ones that were starting to bud again, and added some new ones.

As always, thanks in advance!

Aaron

 

[Dieses Madchen]

What is the pH of your tank? If the pH crashes, the bacteria will slow down on consumtion. It's called a "cycle stall"

Yes, dead plants can cause ammonia.

 

[Autonerd]

Whoops -- I haven't been checking ph as it hasn't been changing, but I just tested and it's at 6.0 (lowest the test will register) down from the usual 7.8. Think I found my problem!

I did some searching, it looks like the solutions are either baking soda or a water change. I don't know my kh but we generally have pretty hard water out here in California. Will a water change solve my problem?

 

[Dieses Madchen]

it might, but you may want to get soem crushed coral or baking soda to bring the pH up. once you do that, the cycle should start again. You can also do a large water change and redose with ammonia. it is probably high nitrates that crashed your pH, so a water change should solve the problem.

 

[Autonerd]

Thanks very much. I just did a 1/3 water change, I'll let everything run for a little bit and then re-test the values and maybe change some more water. If the pH stays still low, I'll add baking soda.

 

[Autonerd]

Well, the water change seemed to do it -- as of this morning my pH is back in the mid-7s and ammonia is down to 0. Nitrates still at 40. I'll do another 1/3 WC today just to be on the safe side.

Thanks!!
Aaron

 

[Dieses Madchen]

One thing you may consider is getting pH-up or adding crushed coral to the tank to keep the pH up. Crushed coral would be best as it will constantly buffer and keep the pH from dropping. During a fishless cycle, you want to keep the pH around 8-8.4 as the bacteria thrive and it speeds up their reproduction. Hope this helps.

 

[Autonerd]

Will that affect the tank long-term? In other words, once the cycle is done, can I let the pH drop to its natural level of 7.8 or so, or do I have to keep it at 8 or above?

 

[Dieses Madchen]

Once the cycle is complete, you can remove the crushed coral that way it maintains a pH suitable for whatever fish you get. What type are you planning?

 

[Autonerd]

Once the cycle is complete, you can remove the crushed coral that way it maintains a pH suitable for whatever fish you get. What type are you planning?

I don't know yet. I got some great suggestions on the forums in an older message, but I can't remember what they wre offhand! I was looking at small schooling fish (I have a 15 gal (US) tank). Corys on bottom, maybe some cardinals... oy, I just can't remember the other suggestions.

Aaron