I think you misunderstand.
I asked why he cannot wait longer. Simple question, not an opinion. Would a 2 L reactor get there, but just take longer?
What I did state is my opinion that think it is ridiculous to use a system where 10 liters may be required. I have no idea if that much is needed or not, But, IMO, I would never use a denitrator that required me to set up a 10 L a reactor. That just takes up too much real estate unless you have a dedicated fish room separate from the aquarium.
Knowing the basics, one is aware the reactor must be big enough to remove the daily nitrate overproduction daily once the desired level is reached. One must have enough sulfur and media to export the daily nitrogen overproduction, only a bit more to lower the level. As explained, in the case nature will lower the level slowly, or one may increase the export rate as desired.
But the reactor must be big enough to be able to consume enough oxygen entered with the nitrate.
Using BADES one does have a very effective remineralization biofilter which may export most nitrogen entered.
In this case, the average daily nitrogen overproduction is NOT known, only the nitrate level to be reduced. Will 2 liter be enough? Maybe! We do not know. As explained, the advice to use 1%+1% is given to prevent the reactor may reach its critical point before reaching the desired level. This if
a BADES biofilm reactor is used, not targetting 0 nitrate in the effluent.
If
a BADES reactor is used, targetting 0 nitrate in the effluent, it is theoretical not possible to reach the target 0 nitrate with only 2 liter sulphur. At least 2% of the system volume of sulphur is needed to remove 150ppm in one passage true the reactor. One must also think about the phosphate content needed for autotrophic denitrification. If a "sulphur denitrator" is used, by which the flow is managed not in function of the nitrogen content but in the function of the DO content to keep the reactor anoxic, using only 2 litre of sulfur may lead to an HS factory if not managed correctly when the critical point will be reached. 2 liter is not enough to target 0 nitrate in the effluent having 150ppm in the influent. As one can not increase the flow, the critical point is the level that can be maintained at the present daily nitrogen overproduction. What if the daily production increases?
What if the reactor is not big enough to remove the daily overproduction daily? Wich probably will be the case as the nitrate content descends. Nitrate is needed to maintain the processes, the reactor water nitrate content may be depleted causing sulfate reduction.
A 2 liter + 2 liter BADES reactor will lower the nitrate level of 150ppm very fast until a certain nitrate level, the critical point, is reached. If 2liter sulfur is enough to remove the daily nitrogen overproduction, which normally is the case, in that case the target can be reached if 0 nitrates in the effluent are not targetted. One must be aware that at a level of 150 ppm to export the daily nitrogen overproduction only a very low flow is needed and the reactor can be used + 90% for denitrification, doing the same at a level of 2ppm only a small part of the reactor volume will be used for denitrification, <30%, the flow must be high enough to supply the nitrate needed to be able to export the daily nitrogen overproduction daily and to prevent nitrate starvation within the reactor. The for denitrification usable part of the total volume must contain enough sulfur to remove the same daily overproduction daily. So, it all depends on the daily nitrogen overproduction to be exported daily, Not on the nitrate level. This if 0 nitrate in the effluent is NOT a target. That is why knowing the average daily nitrate overproduction becomes important, before starting using BADES for lowering the nitrate level.
As the for denitrification usable part is divided over the total reactor volume we not only use sulfur strictly necessary for denitrification but also as a substrate for the growing mixotrophic biofilm making simultaneous nitrification and denitrification possible, using the total reactor volume.
What about a sump?
In most setups, there is more enough space under a +- 500 l aquarium for a bucket of 10 liters.
Having 150ppm in a reef aquarium is exceptional.
Normally a BADES biofilter is part of the system at system startup, by which only the daily nitrogen overproduction must be removed. Anyway, we always advise using a reactor with a volume of minimal 1% +1% as one does not know at setup what bioload must be supported in the future.
A "denitrator" does not change a thing for the carrying capacity of the system and using one does NOT support the bio-load.
Using a BADES biofilter or-reactor the carrying capacity of the system may follow the increasing bio-load while keeping the nitrogen content in balance at the desired level. The nitrate level will stay where you want it to stay as one will have full control over the nitrogen content and export rate. I think that is worth the "real estate" investment on the floor under the aquarium or above the sump. Of course, an aquarium room is everybody's wet dream.
There are methods used to lower the nitrate level which do not need any "real estate", but that is your specialty.
To remove 150ppm nitrate!? It is not my choice to make but I would invest in some "real estate".