Flow Article, apply to Plants?

[Samala]

Hi gang!

I came across this article from Advanced Aquarist which covers a lot of interesting thoughts about water flow and movement in a reef tank.

I got really interested in the notes about gyres in tanks actually. I have a LOT of flow in my tanks these days, the better to keep my pH stable. I'm wondering just how important it is for marine plants' health. I've suspected its very important in the past, but never attempted to quantify it. I'm also sorta intrigued with the idea of keeping the water upward moving, as if it truly were upwelling from a reef wall or incoming towards the shallows from deeper ocean water.

At any rate, I thought the article had some interesting ideas and I think its something we saltwater gardeners should think more about when we construct and maintain our algae/grass beds.

Maybe I should take a flowmeter out to the beds, eh?

>Sarah

 

[graveyardworm]

Maybe I should take a flowmeter out to the beds, eh?

Inquiring minds want to know. :wave:

 

[piercho]

Flow effects what will grow in an area, IME. For instance directly at the outlet of a 20GPM 2" outlet I got a lot of Valonia sp production. This flow was too strong for coral and killed the coral in the same area. At the other end of the flow spectrum, I get Ventricaria in lower-flow areas, especially where detritus accumulates. A smart plant-person like you would have to explain why two algae with similarities in growth form (both bubble algae) would prefer different flow environments. I don't just think its important, I think its the make-or-break factor for some plants, just like it is for some coral.

It also affects growth form IME. The Udotea I grew in my tank did not look much like the fan-shaped wild Udotea I received. The wild stuff is thick bladed with a stout base and dark green color. The fronds on mine were less thick with more surface area and random folds, were a lighter green (under 250W Iwasaki), and the base was pretty flimsy. Less light and no wave energy would be the reason for the difference IMO.

The seagrass bed (eel grass) I see almost daily has strong tidal current with occasional periods of wind waves. Flow can be pretty strong at the surface over the bed at peak tidal flow, I would guess up to 5 knots. Other beds I see are in dead-end bays and seem to have lower production and shorter blade lengths than the beds exposed to higher currents.

I was using a SCWD wave maker to get a bit of wave action going to rock seagrass in my tank. But I kept having problems with the SCWD jamming because some little piece of hard debris gets inside and jams the mechanism. After buying 3 I have finally given up on them. I’ve also grown weary of power heads on a wave maker. What I currently have is a T fitting on the pump outlet. Each ball valve goes to a nozzle, with two nozzles at opposing ends of the tank. I shut one valve and open the other, switching them about three times a day, to somewhat simulate tidal current. It’s low-tech and bombproof.