What was this dicussion about again? Oh yeah...
Quote:
Originally Posted by jcbyrne  In his article in the Tropical Fish Hobbyist that just arrived, Amano says that to monitor CO2, measure the ph just before the light goes on in the morning, and again four to five hours later. If it is higher, the amount of CO2 is insufficient, if it is slightly lower, the amount is adequate. If it is much lower the amount of CO2 is excessive.
So, what do you think? What is "slightly lower", "higher" or "much lower"? |
Focusing on this question and on this alone- Amano seems to base his articles and recommendations on his experience. This experience is largely now based on the ADA system of substrates and fertilizers. This comes into play in a couple of ways.
First, we need to consider the CO2/kH/pH relationship. When kH is very low, ie ~1degree or less, the addition of CO2 can translate into a large shift in pH. This is one of the reasons why pH controllers are not used with tanks using Aqua Soil. Aqua Soil has the effect of removing a lot of the kH buffer from the water, especially in newer setups. The buffering effect of the carbonates (measured in kH) dictates the start end end pH given a certain CO2 concentration in the water. It is pretty complicated chemistry and I won't try to explain it here, but basically adding CO2 to low kH water means low pH. Low pH can be fine in a planted aquarium but only within reason. Crank the CO into an Aquasoil tank and you could see pH values in the low to mid 5's. That is a bit acid and dangerous to play with as far as fish and plants are concerned.
In general, because of many factors involved with AquaSoil and ADA fertilized setups, adding 30mg/l would give a super low pH, which is bad. In addition, because of the ways in which nutrients are available based on pH (among other things) a pH in the low to mid 6's is generally ideal for the plants and fish.
So, the first part of Amano's comment is obvious. If the pH raises during the photoperiod, the plants are consuming the CO2 faster then you are injecting it so you need to increase your rate of CO2 injection. If the pH has a small shift then you will be in what ADA consideres "optimal pH" and if your adding a lot of CO2, the pH will be very low.
Now, obviously this method works for these particular setups. There is no question about that. The crux to this though is that this technique may not work on other types of setups, say with Eco-Complete substrates that actually add buffers to the water.
The biggest thing to remember, IMO, is that we spend a lot of time trying to force
part of a system to work in our particular setup. Amano says to only add a little CO2 and since it works for him why does it not work for me. Well, are you using the system? (rhetorical you here, no one in particular). I completely agree that EI is not the be-all end-all for how to grow plants, Neither is ADA, Dupla, Seachem, PPS, etc. If you want an easy, no though-no hassle way to grow plants that removes all the scary science, then go for a full ADA system; at least in regards to the substrate and fertilizers. This system seems to have the most room for error and the
system is pretty user friendly.
EI and PPS are actually good methods also. Both have their pluses and minuses, their parts I agree with and part I modify for my own use. They are also more similar than many realize. I also know that neither developer of each respective system is very good at conveying the subtle parts or benefits of each. The math behind both is almost genius but it is up to the user to understand and apply it to their particular situation.
For me, the science is fun and I can even enjoy a water change. I like testing and playing with nutrients. I realize I got way off topic here and I apologize. I guess my response to the original poster is that Amano's advice is suitable if you consider the situation behind the advice. Super soft water, Aqua Soil, ADA ferts and lots of patience and cleanliness is the ADA way and his advice works beautifully for that. One system or method or combination if methods do not give the ultimate answers to growing plants. The ultimate answers is to give the plants the nutrients they require for the particular setup and be neat and clean.