Fast Vs Slow Phosphate absorbers

[maroun.c]

Was checking out AMS product range and came to 2 types of phosphate removers:
Super Phos and Super Phos SPS where the differences are as follows:
SuperPhos SPS: Larger granule, Less weight per same volume and its supposed to absorb PO4 slower (assume this is to avoid shocking corals) and it's mentioned to be for ULNS.
SuperPhos:Smaller granule, more weight at same volume.
Both are good for fresh and saltwater... both are GFO.
Any input on the difference between the fast and slow absorption and any pros or cons to each other than a slower reduction and less risk of shocking corals?
By slowwer absorption are they just relying on the larger grain size for less contact and then a slower absorption?wouldn't this limit absorption when the granules get coated with a bacterial film?
Thanks for any input as we have both and I'm wondering which one to go for. I got one of each to try to compare but doubt comparing how much reduction I get with the same volume or weight is going to provide a clear indication on which one to go with.

 

[Randy Holmes-Farley]

IMO, this is marketing stuff, not necessarily useful properties.

One can generally control the rate of phosphate removal by GFO adjusting the amount of GFO and the flow rate through it.

I've not seen data to suggest that phosphate penetration into the pores of larger pellets is slower by an amount that is significant, but it might be. I wouldn't assume there is any special utility to this product unless they showed that.

 

[maroun.c]

Thanks Randy,
I was actually ticked by the fact that they offer very little explanation on this.

 

[badfinger]

Do you need a slower flow rate through gfo for better absorption? Or the more water through the better?

 

[Randy Holmes-Farley]

Lower flow through a GFO reactor will reduce the rate that new phosphate is brought into the reactor and will tend to reduce the net rate of phosphate uptake. For a non-tumbling media, higher flow can lead to faster reduction in tank phosphate, but at a certain point the GFO may break up so you do not want the flow too fast.

Slow flow is good in a single pass system, but that is not how most people use GFO.

 

[Reef Man]

Slow flow means just water flows andnot tumbling the media?

 

[Randy Holmes-Farley]

Well, it may mean different things in different scenarios, but that is one way to think if it, yes.