Drop Checker

[Haveagojoe]

As you can see I am new to TFF and its been a long time since I kept fish,I aquired a 100ltr bow fronted tank about 6 months ago and have set it up as a communtiy tank with about 20 fish in, its planted with the usual amazon sword, vallis, camboba and wisteria but all seem to grow for a bit then start to fail, so I'm thinking about a c02 system but I don't understad what a drop checker is. I am going to go for the yeast system I think because of funds but would like a bit of advise, ihave read the guide on here but its the drop checker tht I can't work out so an explanation of what its for would be very welcome

 

[mark4785]

A drop-checker, from what I can understand, is a common c02 injection system accessory which uses a liquid solution to monitor the amount of dissolved c02 in the water. I think it contains a carbonate hardness (KH) solution, which changes colour in accordance with the level of KH in the water; I think a low KH (indicated by the KH solution turning green) indicates a low PH level and high c02 concentration, conversely, a high KH (indicated by the KH solution turning blue) indicates a high PH level and low c02 concentration. yellow KH solution colour indicates too much C02 and a very low PH/KH level.

The overall purpose of a drop-checker is to let you know how much c02 is dissolved in the water. Too little will cause plants to suffer and too much will cause fish to gasp.

 

[SuperColey1]

The overall purpose of a drop-checker is to let you know how much c02 is dissolved in the water. Too little will cause plants to suffer and too much will cause fish to gasp.
[/quote]

Its basically a Ph indicator. We use a known KH reference as we know that it is isolated from any other Ph changing substances within the tank and therefore will only change Ph due to gaseous exchange.

Therefore as CO2 and O leave and enter the water at the water's surface of the tank it also enters and leaves the water of the drop checker and passes through the part that has air trapped in it and thus you get gaseous exchange between the tnk water, the air in the drop checker and then the drop checker solution.

We then add some Ph reagent so that it is a permanent Ph test of that 'known reference' Kh solution in the drop checker.

We use 4dKH because it is the clearest indicator colour wise to see a ppm of 30ppm etc. You can use 2dKH but then work on the same colours being a 15ppm indicator.

So its nothing really to do with KH. The KH is simply a known reference.

It is in effect a Ph checker.

That is why we don't use tap water or tank water. Both are not isolated from other contaminants and therefore th Ph may change for other reasons than CO2 and give false assumptions of CO2 ppm.

AC