Arturs;33345 said:
In case of ADA substrate and other ones which include peat, checking CO2 by means of KH/pH relationship is incorrect. In my opinion the KH/pH relationship is valid when we use plain gravel in a tank(without peat etc.). We also should not dose other preparates which can have effect on pH(If we want to chceck CO2 by means of KH/pH relationship).
It is necessary to use drop checker in aquarium with ADA substrate because measurment CO2 is not dependent on salts dissolved in the water in aquarium.(drop-checker color depends on level of dissolved CO2 in the tank water only).
Then how might you explain Matpat's 200ppm range of CO2 yet fish are fine?
He uses tap and the pH meter is calibrated correctly, the KH test kit is as well, and the sediment is Eco complete, which has no impact on KH/CO2.
Tap can have other things that influence pH and KH readings in the test kits.
This is why the drop checker tends to be popular, it gives up the accuracy pH and there's a lag of about 2-3 hours, but gets away from any interferences in the water for pH and KH.
You can have PO4's causing issues that are added to tap etc, even if these do not give you extreme examples like Matpat's, even 20% off on the low end would have folks adding 20-30% less than they think they are adding.
You do not know what the CO2 really is(most of us really do not directly), but you seem to think that you do. I don't either without a nice piece of $$ equipment oir a complex DIY set up.
But since a client has the CO2 meter, I can simply observe and verify.
If you do large massive frequent water changes with RO water and reconstitute it, then the pH/KH level should be pretty consistent. I can also verify indirectly by manipulating the CO2 and getting precisely the same response with less CO2 as you see with your plants.
I have and can dose these same ppm's of nutrients and do not have such responses from plants. Give these two things, even without a CO2 ppm reading, I know and can falsify that it's a nutrient issue, rather, much more likely a CO2 issue. I've heard this and seen before many many times, and had plenty of folks say the same things that you have here, this is not a new issue you alone have seen.
It is easy to rule out nutrient causes, we know what they are.
They are much easier to test.
You can also make reference solutions and should, to show that the test readings for the ppms are correct as well as knowing you have at least the ppm's based on adding a known weight to to a known volume of water.
We can measure light pretty well.
This just leaves CO2 as the main variable and it's not as easy as you seem to think to measure it confidently. You are not going to get anywhere and get at the root issue here until you address that.
Plants grow well for only a few reasons/variable, CO2 light and nutrients.
As long as filters are clean, etc other basic stuff(often these can be over looked), those are what you have to work with. I have these same plants and do not have these issues unless the CO2 tank runs out. Then I get similar issues on the same species at the client's. Light and Nutrients are/where the same, only the CO2 changed. Smaller stunted tips, if it's strong CO2 issue, then BBA, some species melt, some stunt, BGA maybe, Hair algae etc. It's not hard to add a bit more CO2 and dose and do large water changes for the next 2-3 weeks or so. Then you can see.
You have wide ranging issues in the tank with many species and then only some plants. What else could do this?
I know of nothing.
And if the plants had been doing fine, prior, and you did "not change anything", then it's virtually always going to be CO2.
Nutrients can be added and stabilized easily. CO2 not always.
Also, as plants grow more, more biomass they also have more CO2 demand from the water. If CO2 is slightly limiting, then some will grow well, others will stunt.
As you add more biomass, you end up with some stunted, some not.
The plant sacrifices some so that the others will grow and hopefully make it to the top and flower etc.
Regards,
Tom Barr
