Reason to Run Low Alk?

[Max93]

That seems to be a popular belief, but probably a gross oversimplification. Unless you are driving residual N and P very low (like below natural seawater levels) with media or chemicals, there is no need to keep alk low to limit calcification.

I think that all of this is just based on some bad evidence from back when people wanted to do Zeo and true ULNS, but that has not been popular with the masses for at least a decade. Those that do use this do indeed usualy keep their alk lower than most.

I keep my alk around 7.0 because that is what is in the ocean and I like to stay around there.

If your acropora are constantly dying, then alk at 8.3 is not the reason.

What do you think it is? I can’t seem to find any direct answers.

the best and most logical answers I have read are to keep alk closer to 7, like NSW. That’s the only thing I have not tried.

mind you I recently upgraded my lights and went through a hypo period in my display so currently no Coral and I haven’t added Corals since. My par reads 400+ in most areas now, lowest at 280 at the bottom.

 

[Spare time]

It might be important to explain where the fear of higher alk and "burnt tips" comes from. In a nutshell, when building blocks are very low, then calcification happens faster and tissue cannot grow as fast since they need new building blocks to make new organic tissue. The skeleton grows faster than the tissue can grow and after a while, the exposed skeleton gets stressed and the tissue stops grow. True "burnt tips" are a result of growth, not existing tissue dying back - this is something else.

This usually only ever happened when people used media/chemicals to lower building blocks lower than Natural Sea Water levels... which is nearly impossible without using media/chemicals. Keeping the alk lower would somewhat growth-limit the calcification process where it would not outgrow the tissue.

Keep in mind that the ocean is about .1N, .005P and 7.0 dKh. Ultra Low people wanted to get lower than this for some reason... so they had to keep their dKh lower too.

Calcification decreases as N and P rise, so having lower dKh will not really harm anything since growth is slower anyway. The amount of slowing growth depends on the species where as some might not slow down much and others might nearly stop at moderate level.

In general, I don't think that it matters much unless you are looking to be at a top 10% level for growth and color. I also do not think that dKh swings or changes account for nearly the amount of issues that they get blamed for... I have never had issues moving frags, buying or selling. At best, if a coral is weak and otherwise not healthy, it might be the final punch, but not too much more than this.

It's also important to note that natural levels of nitrate and phosphate are more harmful in our tanks as corals are eating in the wild where as skimmers, uv, and such sterilizes aquarium water from these food sources, essentially starving the corals. It's also difficult to feed the right/preferred food for each coral as again our tanks do a poor job of replicating wild reefs

 

[Spare time]

Basically the idea is that alk is a limiting factor for coral growth and higher alk (to an extent) encourages faster growth. People historically thought ulns were the best practice but mixed with high alk results in burnt tips as previously mentioned

 

[jda]

If during hypo, you corals were not getting ammonium as a substitute for fish waste, then I would put my money on that. Residual N and P levels are no substitute for nitrogen from ammonium/ammonia and P in all form from fish waste.

I know that the recent internet trend is to dose or add N and P on the backend as a way to "feed corals," but id does not do that... at all. Nitrogen from ammonium/ammonia is the way to get N to the corals. Aminos and the coral foods on the market are no substitute either. Hypo is hard on coral.

You cannot underestimate changing lights, but that is so hard to quantify and should be set moving forward, so even if this was it, nobody would ever know and it is in the past.

 

[X-37B]

It's also important to note that natural levels of nitrate and phosphate are more harmful in our tanks as corals are eating in the wild where as skimmers, uv, and such sterilizes aquarium water from these food sources, essentially starving the corals. It's also difficult to feed the right/preferred food for each coral as again our tanks do a poor job of replicating wild reefs

I run a filter sock and over size skimmer in my 120.
I feed heavy and practice heavy in/out. I do not feed the corals the fish do.
My po4 runs .05 now and no3 runs <3.
Alk is at 7.5-8 now.
This has worked well in my 3 systems im currently running.

 

[jda]

What do you think that elevated residual levels of N and P are doing for coral? There is actual science that says what is happening... mostly bad things like limiting zoox growth and slowing down calcification. As long as there is a trace, then more is not helping corals, especially the SPS.

I am not saying that nitrogen and phos are not important, only that the corals should not be getting them from nitrate or excess accumulation of po4.

I keep natural levels of residual levels of N and P in my tank - about .1n and 1-3ppb of P. Care to find tanks with better growth, health and true color? I also feed a ton and export a ton and none of my corals are hurting for any kind of building blocks at all - they have all that they need in the right forms for optimal absorption.

 

[homer1475]

Love how everyone is quoting BRS about high alk = faster growth.

Yet no one considers that a high alk equals more dosing. Guess who sells, developed their entire buisness off of selling 2 part, and made all their money off simple 2 part?

LOL the hype machine that is BRS is real, and obviously works just as evident from how many times that video has been quoted just in this thread.

With that said, I have run my alk anywhere from 6 to 10. While I did notice a small growth uptick with higher alk, I'm not trying to squeeze every last bit of growth out of my corals. I have limited space, and no place to go with frags(clippings), so I tend to run lower alk to limit growth a very small bit. (NSW levels of 7 -7.3)

 

[X-37B]

I ran alk at 7 for over a year and growth was not affected.
I currently run alk at 7.5-8 with 7.5 the target.
People forget that the average ocean alk is 6.5. Many will argue the point without research.

Their are large coral sellers that will say the ocean alk is 8-9 go figure.

 

[Max93]

Makes so much sense. After I get my tank stable again I am going to try acros again. I will aim for 7-7.5 alk versus 8.3.

All I did research on was the BRS videos as well. Time to switch my strategy.