Alkalinity Question

[mattyg18]

I've been monitoring parameters closely for my 8 month old 60g cube and in the last month the alk has slowly been decreasing. I'd like to attribute that to the corals growing, increased coraline, and the addition of fish (which everything is doing well). After doing research on this I started dosing baking soda (at the recommended amount) to my ato. This past Saturday my alk reading was 6.9 and now its at 8.9. I'd like to get it to around 10. Once it hits 10, should it maintain that number or will I need to continue dosing baking soda? I'm still new at this, never have dosed anything, and not sure if this is the norm or not. I've read about adding kalk (which i've got) and that could help maintain some parameters.

Please let me know what you guys think.

Thanks again and Happy Thanksgiving!!

 

[ColoReefer970]

Slow and steady... (maybe not slow so far)

Why 10?

Ultimately you will need a maintenance dose

 

[NS Mike D]

Only dose to supplement elements that are being consumed faster than replenished with water changes - which you can measure by testing. That being said, kalkwasser replaces both calcium AND alkalinity - so use that only if you need to raise/maintain both to keep up with consumption. Kalwasser and two part dosing are common since both calcium and alkalinity are usually consumed together.

As for how much baking soda, the online calculators which provide the recommended amounts will include the estimate of how much a dose will raise alkalinity for the give tank volume - so you can do the math to determine how much baking soda was dosed, then calculate how much that dose should have raised the alkalinity and then subtract 8.9 from that number to determine how much was consumed during the week and that should be your maintain amount.

 

[thegrun]

While an alkalinity level of 10 will give you faster coral growth assuming you keep your calcium level near 450, it will do so at the expense of coral coloration. I prefer an alkalinity level at 8.3 and calcium at 425

 

[NS Mike D]

Slow and steady... (maybe not slow so far)

Why 10?

Ultimately you will need a maintenance dose

Do some searches here on alkalinity and nutrient level. While debatable, there appears to be a correlation between growth and color - lower KH, NO3 & PO4 for color and higher for growth.

IMO, pick a range for all three you want to target and hold it a steady as you can without making it inconvenient (it is a hobby after all). After a while you can decide from you observation if you are happy with the result or need to change your targets.

 

[JoeBatt]

Do you also monitor the Calcium? What has that been doing? As you increase the Kh you need to increase the Ca, you also need the Mg at a correct level or you will just end up precipitating the Kh out that you put in.

What corals do you have in the tank? SPS LPS?

10, I would suggest is a little high, though within limits and at that level you could find you start to encounter a few problems with SPS corals.

Unfortunately just ramping up the Kh to 10 isn't as easy or as good as it sounds. In my tank, I try to keep it around 8, with the main target being to keep any daily variation very small. My variation is usually not more than 0.15dKh per day.

Kalwasser is probably a better solution for you when you have got the Kh and Ca where you want them. It will maintain the levels, but don't try and use it to increase them, it doesn't work.

 

[mattyg18]

It seems everyone keeps their alk at different levels and honestly I'm not sure where it should be. I chose 10 based on the guy at the LFS.

What do you recommend for Reef?

I though it raised too fast but I followed the instructions on the dosing site. This morning I mixed whatever remaining ato water left in the 5 gal with fresh RODI water to slow it down.

 

[NS Mike D]

I got these numbers from a number of sources, the targets (Growth and Color) I used from Red Sea's program*. I keep these at the top of my test results spreadsheet for reference.

I am not vouching these as being gospel and will bow to the more experienced members as they contribute their insights. While my searches to find these numbers bordered on obsessive, my actual tank experience is limited to about 20 months.


* Edit note: Red Sea has different numbers for different type tanks - softies, lps, sps. They suggest that if you have a mixed tank to target the lower numbers (ie. lps or sps). Since I have a mixed tank with a few sps, I use their sps targets which are less forgiving.

 

[NS Mike D]

It seems everyone keeps their alk at different levels and honestly I'm not sure where it should be. I chose 10 based on the guy at the LFS.

What do you recommend for Reef?

I though it raised too fast but I followed the instructions on the dosing site. This morning I mixed whatever remaining ato water left in the 5 gal with fresh RODI water to slow it down.

It depends on what you have in your tank, what the other parameters are and what you are trying to accomplish (see my above post).

At 10 you are smack in the middle which is fine, especially for "new to the hobby". Over time, you may wish to gravitate to a more demanding low nutrient SPS tank.

BTW, look up magnesium here. It's like the referee that keeps the calcium chloride from combining with the sodium bicarbonate and precipitating out of solution. Thus, it is important to keep your Kh, Ca & Mg in balance. It's best for your tank inhabitants to raise (or lower) any parameter slowly to avoid stressing them, but another unintended consequence of changing these three quickly can get them out of balance and throwing off your numbers while they seek to get back in balance.

 

[jml1149]

Instead of dosing baking soda into your ATO, perhaps look at kalkwasser.

 

[homer1475]

Never heard of putting baking soda in the ATO? Wouldn't that cause the parameter to always fluctuate? I know in my tank, depending on the days conditions, my evap rate varies. So my ALK would always fluctuate. Maybe today I evapped 2 gallons, then tomorrow with the windows open I only evap 1. That would cause some hellish ALK swings.

I would look into dosing kalkwasser in the ATO. Once you reach the levels you want, kalk will maintain them.

 

[mattyg18]

Wow and thanks for all of the replies. I wasn't expecting that. So my Ca has been holding at 500 for a long time and my Mg has been at 1500 as well for quite some time. Not sure why these numbers are high but i've been assured its nothing to be too concerned about. Thats why i'm hesitant about dosing Kalk. I'd rather not bring my Ca any higher than it already is.

Here is the link about the baking soda:

http://reefcentral.com/forums/showthread.php?t=2171141&highlight=raising+alk&page=3

And here is the calculator i'm using which was also found on RC:

http://reef.diesyst.com/chemcalc/chemcalc.html

Agreed that the ato may not be the most consistent dosing because of evaporation but its more gradual than just dumping baking soda in to the tank. For now I put a fresh batch of RODI for the ATO and i'm going to just monitor the Alk for the next week or so and see what happens. Its at 9 right now so I'll see how things react before adjusting it.

If anyone knows of a better way of dosing Alk (other than Kalk because of the Ca increase)please let me know. I'm open for suggestion.

NS Mike D - Thanks for the chart. I just printed it up. I'm in Commack BTW and actually from Huntington. Small world.

I have a variety of corals including zoas, birds nest, mushrooms, acans, torch, purple digi, and a bunch of others which I don't know the names. Everything seems to be doing well though.

For fish i've got 2 small clowns, a bangai cardinal, goby, fox face, and blenny. Dont think i'm adding anything else.

Once again thanks for the replies fellas and have a Happy Thanksgiving everyone!!

 

[homer1475]

Yes I dose baking soda also, but I mix 1 1/8C in a gallon of RO/DI and use a dosing pump to put in 187ml a day spread out over 24 hours. Which is the method that thread is talking about. Its Randy's recipe, well known and exactly how I dose. Have you read the original article?

Randy's Recipe Original Article

I just don't see how with the varied evap rates with an ATO that can not cause alk swings? Now I see where your getting your info, I see your misinterpreting it.

 

[tkeracer619]

kalkwasser is a great way to go but do not use it to raise alk/ca. Only use it to maintain. You can easily spike your ph if you add to much at once.

Also, don't dose in your ATO unless you have a peristaltic pump type ato with dual float switches (one as a backup). You can easily nuke a tank with an automated dosing setup.

 

[mattyg18]

Homer1475 - Thanks for the original article. Had no idea thats how it was done. The one I read just says to dissolve the baking soda in RODI which is what I dit. Well anyways my alk seems to be ok for now at 9 and I need to set up a dosing pump now. So time to do my research on dosing pumps. This hobby never ends....lol

 

[JoeBatt]

If it's at 9 and stationary, keep it there. Strive for consistency and stability rather than hunting a specific number. 10 is no better than 9 or 8 and vice versa. It is the stability that grows the tank