Dosing levels and wc

[Andrew_bram]

So why is it you can only raise alk by less then 1 dkh per day or mag by 100ppm a day with dosing. However, when you do a water change you can raise them well over that amount depending on that salt you use. For instance with kent salt I consistently test at just over 10 dkh however I run my alk at say 8.5 When I do a large water change it puts me well over 1 dkh per day. Note these are not actual number as I try to run way closer to 10. One of those food for thought things.

 

[jda123]

Who said that? Sometimes, I might just dump a few tablespoons of baking soda right into the overflows if the Alk is too low - especially on new tanks before I get the reactor dialed in.

I think that the general advice is to keep dosing to just the bare minimum to just keep levels stable and your hands off of the dosing pums. Lots of people cannot even succeed with this and changing the settings every few days would probably be a recipe for disaster for most.

In the water change water, they are also totally mixed in the solution and not being added into existing tank water... so the actual processing of the raising is different... offline vs online.

 

[Andrew_bram]

Dosing levels and wc

It's just a general rule out there. I am not saying you can't dose one dkh a day but it is said not to do it all at once. How is it different from doing a wc. Raising is raising doesn't really matter how correct. If I were to dose 120 ml of alk or do large water change other than ph effect what's the difference. I like thinking outside the box.

 

[jda123]

Probably not much. I guess that there could be some issues of mixing it in the tank, but I do it when I need to and don't sweat it much.

On the flip side, adding in higher SG mixed saltwater is better than just adding salt to the tank too raise the SG some.

I really think that this is it: you are smarter than the general rules, but lots of people need them. Just imagine all of the people that just follow the directions that RHF or BRS put out 2 part and actually have no idea what they are actually doing to their tanks.

 

[Andrew_bram]

Well awareness is a big thing for me hate seeing people fail and give up.

 

[jahmic]

I think one of the concerns with raising the alk to quickly is actually precipitation. Because of the dilution in changing a large volume of water via a water change, that's less of a concern.

The other issue is pH swings...but again, changing 20% of your water over a period of several minutes is going to be friendlier than suddenly spiking alk by adding a buffered alk solution to your tank.

That being said...I recently had an issue with my 20gal after a 25% WC due to a sudden change in alk. I blame the small water volume since the change happened within a minute or so, whereas a 20% change in my larger tank takes several minutes due to the volume of water being changed and the increased head pressure of pumping out of a tall drum vs a 5gal bucket right next to the 20gal.

 

[Andrew_bram]

I think one of the concerns with raising the alk to quickly is actually precipitation. Because of the dilution in changing a large volume of water via a water change, that's less of a concern.

The other issue is pH swings...but again, changing 20% of your water over a period of several minutes is going to be friendlier than suddenly spiking alk by adding a buffered alk solution to your tank.

That being said...I recently had an issue with my 20gal after a 25% WC due to a sudden change in alk. I blame the small water volume since the change happened within a minute or so, whereas a 20% change in my larger tank takes several minutes due to the volume of water being changed and the increased head pressure of pumping out of a tall drum vs a 5gal bucket right next to the 20gal.

Interesting so let's consider a dosing pump raising over a dkh a day to get you on target. You could raise fairly slow to help avoid large ph fluctuation so in theory this would work. I just have been noticing something's lately and I am home sick which is never a good thing for my brain lol. I have no desire to raise this fast as I will just continue my wc to get to target since dosing isn't keeping up quite yet. Just added a lot of corals so demand went up significantly.

 

[jahmic]

I don't see why not. I studied biophysics in college...so it's rare that I miss an explanation or something goes over my head in this hobby....and I've seen no scientific explanation on why the 1dkh rule is a hard cap. If there is one ...please someone point it out since I've been searching for that answer as well.

I know that sudden changes are potentially bad, and concentrated solutions being added directly to the tank can burn coral due to local changes in parameters...but can't see why a slow drip to raise alk by more than 1dkh in a day would be detrimental.

 

[Andrew_bram]

I don't see why not. I studied biophysics in college...so it's rare that I miss an explanation or something goes over my head in this hobby....and I've seen no scientific explanation on why the 1dkh rule is a hard cap. If there is one ...please someone point it out since I've been searching for that answer as well.

I know that sudden changes are potentially bad, and concentrated solutions being added directly to the tank can burn coral due to local changes in parameters...but can't see why a slow drip to raise alk by more than 1dkh in a day would be detrimental.

Do you think same rule applies for that mag rule of 100ppm a day.

 

[jahmic]

Although I've messed with dosing more than 1dkh of Alk in a day, I have not played with excess Mg dosing. That being said...

Do I think exceeding 100pm is OK?

No. Mainly because Mg has a direct impact on active transport across cell membranes. Bacteria rely heavily on magnesium for active transport, as do simple inverts such as snails. Pretty sure you could shock and/or kill snails by dosing Mg too rapidly.

 

[Andrew_bram]

Although I've messed with dosing more than 1dkh of Alk in a day, I have not played with excess Mg dosing. That being said...

Do I think exceeding 100pm is OK?

No. Mainly because Mg has a direct impact on active transport across cell membranes. Bacteria rely heavily on magnesium for active transport, as do simple inverts such as snails. Pretty sure you could shock and/or kill snails by dosing Mg too rapidly.

You sir are a valuable tool. I have always felt this was just hearsay but who knows. Would love to see the people that say this back it up

 

[jahmic]

Everything I read in reefing has only addressed high Mg levels and their effect on inverts like snails. I'm not certain a sudden increase would cause the same problems...but it would make sense that a rapid change would cause the same effect.

Calcium transport pathways in cells are regulated by magnesium. High levels of Mg block Ca transport, which blocks nerve function and relaxes muscles...which is what "shocks" snails into paralysis. Cells do have redundancies to help offset those effects...but at a high enough Mg concentration Ca transport is effectively shut down. A rapid increase in Mg might not have a sustained noticeable effect...but Ca transport and enzymatic activity could easily be effected by that increase until the cells adjust to the change.

It would take lab testing to find results...and I haven't seen any...but just to be safe I'd avoid overdosing Mg. It's pretty critical in cell function.

 

[Andrew_bram]

Well I will stick to that rule for sure then lol.