I believe hydrogen sulfide is the black patches in the DSB...
Actually hydrogen sulfide will not form in the DSB if the DSB does not exceed 4 inch... From what i experience...
The reason why a plenum system will prevent the formation of hydrogen sulfide is becos the gravel is being sandwiched between the highly oxygenated aquarium water circulating above it and below it the plenum water, which maintains a low but generally stable level of dissolved oxygen... So being sandwiched between these oxygenated zones tends to prevent the formation of hydrogen sulfide...
My 2cent...
Actually, I quite disagree on this statement...
Plenum will actually prevent the formation of Hydrogen Sulphide... And Plenum also require a considerable amount of Sand although less than DSB...
I think you got the whole plenum thingy wrong...
It seems i have gone off-topic too...
Pai seh... Pai seh...
It is becos hydrogen sulphide is produced due to the anaerobic condition in the sandbed, if i am not wrong... So when you introduce air into the setup, it increase the O2 concentration in the tank, so the hydrogen sulphide will decrease abit...
It is a small one huh... you enlarge untill like very big.. Hehe... If you ever frag the red mushie, let me know... Exchange with you a pink mushie... lol...
Dan... Tot the water outlet of the power filter will cause the water to splash and make a lot of micro bubbles in the water... How you managed to solve that prob or you dun have that problem...
Thankz...
Too bad... Me, die hard fans of sly... Agreed that he sang quite badly last nite... But will still support him... Hehe...
Maybe i am prejudiced against Taufik... Dun quite like him but i admit he sings very well...
Maybe you could refrain from adding any livestock for the time being... Let the water parameter stablise first... Maybe for a week or two...
When you add your fishes... Try to acclimatize them... Will have a better chance of survival in your tank... The best method is to use the dripping method...
You will need a air tube, a air tube control valve(those green color one) and (of course!!!) a suitable size container or plastic tank... And a air pump to provide circulation during the acclimatization...
Step 1: Pour all the fishes together with the water into the container...
Step 2: Fix the control valve to the air tube ... And start the siphon by ###### the water from your tank to the container...(be careful not to drink some of the tank water)
Step 3: Den just control the drip rate...(i normally do 1-3 drops/sec)
Step 4: Pump air into the container to provide some circulation...
Step 5: Wait untill the water is 200% of the intial level in the container... If you wan to drip longer by all means...
Step 6: Pour the fishes and some of the water in the container into your tank... Want to pour all or some water, up to you...I normally dun pour all...
This will ensure that the fishes will slowly get used to the water para in your tank... Will have a better survival rate... Hope it helps...