Simply Koi and More Koi

A bit of a tongue in cheek heading but ...
For a bakki shower running with BHM what would be the ideal pH and KH (or anything else you think relevant) to process the most ammonia, nitrite and nitrate?
The reason for my question is that for my fish's sake I'd like pH to be 7.0 but I seem to be finding I'm not processing much nitrite with the KH as low as I need it to hit a pH of 7.

John,

Nitrifying bacteria are often described as "eating" ammonia (in the case of nitrosomonas) or nitrite (in the case of nitrobacter) but they don't actually eat these compounds as a nutrient. Like us, nitrifying bacteria are carbon based life forms and what they actually need is to assimilate carbon from their environment in order to grow and then to reproduce by splitting into two bugs which then grow and each split into two more bugs and so on.

Ammonia bugs use the chemical energy released by oxidising (converting) ammonia to nitrite in order to help them do this and nitrite bugs use the chemical energy from oxidising nitrite into nitrate.

There is a good deal of energy to be obtained from oxidising ammonia but very little from oxidising nitrite so the ammonia bug is big, strong and tough compared with its puny cousin, the nitrite bug. This is why ammonia bug colonies mature quickly in a biofilter and nitrite bug colonies mature comparatively slowly. It also explains why, if water parameters become less than optimal, the nitrite bug colony suffers first and to a greater extent.

The optimum pH for nitrobacter is around 7.3 to 7.5 and they need a good supply of carbon which they obtain from KH. So by using such means as RO to make the water soft for the (disputed) benefit of the koi, we make the environment less than optimal for our bugs, especially nitrite bugs, so they don't work as hard for us as they would in water with a higher pH and KH.

Thanks Manky,
7.4 it is then!!
By pure coincidence that's exactly what I'd set my controller to. 7.15 wasn't working for me (I'd read in a sewage treatment document 7.15 was optimal for nitrite processing, it appears they were full of something (sorry))

I would think full of nitrite John lol

hi John

don't forget your koi the blood pH is around 7.8 as is ours. In order for their gas exchange at the tissue to take place efficiently you need to maintain this blood pH

The blood picks up oxygen at the gills and transports this around the body, as the tissue uses previously deposited O2 this used oxygen is now Co2 and this drops from 7.8 to a much lower figure this is the clue the haemoglobin needs to off load the O2 and pick up the co2 and the cycle continues

dropping to 7.4 puts their blood pH and oxygen transport in jeopardy

dunc

Duncan,
Are you saying 7.4 or lower is a bad idea for the fish?
I thought 7.0 was the ideal for the fish.
I'm going to find a hobby with right and wrong answers (Scrabble perhaps!)

John the carps blood chemistry is a pH of 7.8 as is ours what's your take on it mate? as water is constantly going in and out and a high pH is the haemoglobins clue to pick up an O and a drop in pH at the tissue is the clue to drop O2 and pick up CO2

if you going to run low pH you really aught to know the reasons why your doing it and what to expect other than somebody said it the way to go but not knowing why?

dunc