I can't imagine any reason the ammonia is so high and the pH drops so fast except that you must be feeding too much. It's should be a simple equation. If there wasn't excess decomposing material in your tank you wouldn't have this happen. It's not that hard to see that there is way too much decomposing stuff, and the only thing it could be other than a dead rotting fish is excess food haveing the fish produce excess waste period. Think like an eskimo with their dogs and keep your fish hungry. That has got to be what is going on here. Fish will eat as much as they can and they don't need that much food.

My fault, I reread your post and saw that you said "replaced" and not "cleaned". I know you know what you are doing which is why I said "you probably already know". You sound like you are doing everything right, but adding 6 fish to a 20 gallon probably did stress out the biological balance. That is quite a bit to be adding at one time, but it is not crazy or anything and I would be surprised if that alone got you to 3 ppm. Maybe Peter is correct and it is an over feeding problem. Does alot of the food hit the substrate uneaten? Also, I know when I first started up my cichlid tank, I realized that I had to remove the egg crate on the bottom and vacuum the food that got caught down there. I would vacuum the substrate, but the food that went down below the egg crate wouldn't get sucked up. I start to see a sall spike .25 ppm, so I thought and thought and that turned out to be the answer. Do you have any areas in the tank or anything underneath your substrate where food and debris can be building up?

Yes my ph was getting the lowest reading on the test kit.... a 6.0. Peter, i unearthed some detritus on my last water change the other day... and then changed the water, so there can't be anything decomposing unless its under the gravel filter, but doubtful.... i would have shown ammonia problems much earlier than today.

Normally my ammonia is never above 0.50 so to see it this high was a big shocker to me, especially since my only problem really has been the ph. Very odd. I just changed 50% of the water. I also tested nitrates to make sure i hadnt minicycled and results showed 2.5 ppm.

I will keep the wood out, and see what happens to ph over the next few days. I will also monitor my ammonia. I clean the gravel pretty thoroughly, but i do have a ugf which i have two powerheads hooked up to... I havent had an ammonia problem until today (aside from spikes in my cycle, but im cycled now). I feed sparingly and i would easily say no food hits the substrate (maybe a tiny flake every now and then, but nothing really). I have learned my lesson with overfeeding in the past. My angels eat about 5 granules each, and i hand feed them so it hits the surface for about one second before its swallowed. My rasboras now steal some granules, and munch on a few tiny flakes... nothing hits the bottom, so i dont believe its overfeeding.

I'll test tomorrow... it might just be from my last diggin around for detritus...maybe it kicked up something ugly, who knows... this was a shocker, i thought id be clear by now... every time i solve one thing another pops up!!!!! hate to be so burdensome, but thanks Miami and Peter, u two are a life saver

Hmm maybe the wood was rotting as you previously thought. Either way it seems to have been my ph problem for the time being. As for deeper gravel, my tank actually sits about an inch and half below where you see in the pic... my stand covers the bottom inch and a half of it so you can't see it... plus i have a slope to my gravel where it sits high in the back where the risers are, and gently slopes to the front... i hear this helps for a ugf. I definitely have cycled though, because i have achieved nitrates and kept them for over two weeks now... zero nitrites, and fluctuating ammonia which up until now had steadily been going to zero with my water changes. After today's water change of 50% my ammonia is down to 1.0 ppm.

I think i screwed things up adding those new fish! damn lil rascals have turned my settled world into a bit of a mess for now. But yes Peter... this cycling was a hard thing for me. Next time i have a great idea for a cycle, it might have been done already, but its half fish half fishless: basically you cycle how you normally would with fish... but you do regular water changes. In a separate small tank, you have it fishless and never water change, so that ammonia builds up like crazy... once that small tank cycles, and it should be quick, you can move the substrate and filter to the regular tank.. which should allow it to cycle in a matter of days. This allows the fish to remain healthy, and speed up the cycle process... just an idea.

Peter, i felt the same relief upon returning 6 barbs and a bala shark... but now ive done it again with these rasboras... they little but they poop a lot.

My PH today was 7.4 again, so thats a relief. My ammonia is still high, about to do another water change. I think my biological filter hasnt caught up to the 6 new fish... which explains the ammonia spike. Hopefully im correct. All other variables clear. Will post results for Miami and you.