Alkalinity question

[mgranato]

I just recently switched from Salifert to Seachem for testing my alkalinity. My reading with the Salifert was 10.2 dKH. I was getting a total alkalinity reading of 3.0 meq/lusing the Seachem test. I'm very fuzzy on the differences between dKH and total alkalinity, but Seachem recommends a range of 4.0-5.0. Should I be trying to increase my alk to get into this range, or are my original readings (10.2 dKH/ 3.0 meq/l) in an acceptable range for an SPS tank?

 

[trido]

4.0-5.0. Should I be trying to increase my alk to get into this range, or are my original readings (10.2 dKH/ 3.0 meq/l) in an acceptable range for an SPS tank?

That depends. Are your corals happy and growing? My dkh has been at near 10.2 for the life of my tank and I have only recently been able to keep my Ca. over 400. I have always had good growth and polyp extention. The Idea of Ca. 450 and dkh 11.0 are just target numbers. If you are near there and have the growth rates that you would expect there is probably no need to do extra dosing just to keep your numbers at text book levels.

 

[Six-line Wrasse]

I agree with the above post. Consistency is key in maintaining a health, thriving system. Also, I rarely have a Ca level above 375 and my tank has been doing very well for the past year and a half. I'm not saying it is the best for it, but if there are no signs of stress and you're getting good polyp extension, I wouldn't worry.

 

[mgranato]

Thanks for the responses. I'm also of the school of let the animals tell you if things are good or not. I'm also not one to seek max numbers with Ca and alk (my Ca stays at 350). But yes, the corals are growing and with good polyp extension. My main concern was that I didn't want to be fine with a short term reading only to suffer long term because of it. I'm just not sure what the difference is between dKH and total alkalinity.

 

[trido]

A question for both of the last two posts. Do you test for magnesium? My Ca. was steady at 370 no matter what I did, until I brought my Mg. up to 1350.
On another note. I use IO salt. MY make up water tests at 320 Ca. and 10.2 dkh. Every time i did a water change I lowered my Ca. levels. Now I dose my WC when I do them.

 

[spaulr]

One more item to note...you will also have toubles if your salinity is low. I'm pretty sure those 10-12dkh, 450ca, and 1400mg "target" numbers are a MAX for a specific salinity level (1.027 or 35). Lower the salinity and all the above numbers will drop.

 

[ZooKeeper1]

Seachem salt is high in borate. The recommend a higher alkalinity than normal to make up for that fact. Borate is part of alkalinity but not used in calcification. I recommend keeping alkalinity around 3.5 meq/l when using salts with more normal borate levels.

 

[mgranato]

My mag is 1250, it was at 1100 (couldn't get the Ca above 310 until I realized what was keeping it down). I use Tropic Marin for 25 gallon changes every other week. If I remember correctly the new water tests at Ca 350-360, dKH 10, and Mag 1225-1250. My display specific gravity is 1.026.

Unless someone has good advice to the contrary, I think I'll keep the dKH at around 10, try to bump the Ca towards the high 300's, and maybe bump the Mag up to 1300-1350.