Hi all
Lately I have been watching much more planted tank videos than pictures. This is because in just a few seconds you can understand/see much more things compared to a picture. If you watch any successful planted tank video you will see that flow velocity is sometimes strong and sometimes not at all… so why this?
Well, IMO a planted tank is like a complex equation in which there are a lot of interdependent variables. In our narrow-minded vision on planted tanks, we try to fix some reference values for each of them, but the fact is that it is much more complex than that. Once again IMO it is much wiser to pay attention to the variables which are more important on the final result, so you can focus on them.
A vast majority of the questions in forums are something like “is this light good?”, “is that flow ok?”, “is that fish stocking ok?”, “is that fert dosing ok?”, etc. (or just a help call when things went wrong, something like “how can I get rid of this algae…” which of course is more or less the same kind of question). And the most sincere and best answers are the ones saying “well, it depends on…”. But we don’t like these kinds of answers, we still prefer someone saying: if you have X problem, the solution is Y. For that tank volume you need X light, Y flow, Z ferts…
So, as you may be expecting now, my answer is: there is enough flow when the rest of the parameters are good enough. In other words, if your Co2 is perfect for the light you have, plants have enough ferts, you have the right plants for your setup, you have good and active growing, your filter turnover is enough for this particular configuration, you have loads of plant biomass (and add here whatever you already know from this forum), your flow velocity would be ok.
I guess there might be a kind a threshold/rule of thumb for flow, as there is for example for filter turnover, but once again someone will say “I run a tank like this with half the value you are mentioning…”. Of course use also common sense: blowing your plants and substrate is not a wise option, so there you have what you don’t want as flow velocity. Below this, well, it depends on… 🙂
Jordi