Alk causing coral deaths?

[circusordie16]

so ive had my little reef tank up for a couple of years and its been pretty much problem free for the whole time until recently. ive been losing a fair amount of corals for reasons i cant identify. i havent changed anything and its not pests of any kind. ive lost some plating montiporas and an encrusting montipora while another encrusting montipora 5 inches away is fine. ive lost birdsnest and acan lords and micros. at the same time however ive had a millepora, acan echinata, chalice, ricordeas, one encrusting monti, zoanthids, and other micros doing great. i had some cases of rtn, some of stn, and my acan lord polyps just receded and fell off. so i have no idea whats going on relaly but i think i may have found the problem but im wondering what others think.

 

i tested the water in my tank before a water change:

salinity = 1.025

phosphates and nitrates = 0

ca= 380

alk=7

 

the freshly mixed salt water i use for water changes:

salinity = 1.025

alk=10 or 11, not exactly sure when it reached the endpoint

 

so my guess is that the low alkalinity and the swings in alkalinity from water changes may be causing problems with some corals? anybody else agree? but my question is why wouldnt other corals experience problems as well? any other possible sources of problems that im missing? im using reef crystals and thinking i might just get a new bag of salt or try another salt brand and see if that helps but im not really sure what to do. any suggestions would be great.

[vangvace]

Could be. Do you know what your pH and Mg levels are?

 

How often are you doing water changes?

 

Have you been dosing between water changes?

 

I just skimmed you 5g long thread. Beautiful corals. I hope it isn't that tank.

[filefish949]

phosphates and nitrates = 0

ca= 380

alk=7

 

these are right on the edge. I have experianced losses at those levels what test kit are you using?

[Urchinhead]

Ca is ok. It just means that you will not see allot of growth.

 

Alk is about a point too low for SPS.

 

It could be because of the Alk or it could be because you are causing a micro swing that is too high in the area where you are putting in your new water and thus burning your corals. Going from a 7 alk to a 11-12 alk will cause a burn if the solution is concentrated. The reason the other corals are not affected is that the solution dilutes enough before it hits them.

[divecj5]

It could be because of the Alk or it could be because you are causing a micro swing that is too high in the area where you are putting in your new water and thus burning your corals. Going from a 7 alk to a 11-12 alk will cause a burn if the solution is concentrated. The reason the other corals are not affected is that the solution dilutes enough before it hits them.

 

I think you might have hit the nail on the head with this suggestion....do you dose in a high flow area or in the same area each time? Seems like if you did and if it was a low flow area, the corals in that area are getting blasted with huge swings in not only Ca but Alk.

 

Just wondering though since you've said that you have experienced not only STN, RTN, but also losses with LPS as well. Have you noticed the tips on any of your SPS turning really white...not growth tip white but Alk burn white.

[circusordie16]

Could be. Do you know what your pH and Mg levels are?

 

How often are you doing water changes?

 

Have you been dosing between water changes?

 

I just skimmed you 5g long thread. Beautiful corals. I hope it isn't that tank.

 

i dont have test kits for ph and magnesium so i dont know what those are. i do about 20% water changes every week and dont dose anything. nothing goes in or out besides RO top off water and maybe a freeze dried krill if i feed the corals. and sadly it is the 5gallon tank thats been having troubles.

 

these are right on the edge. I have experianced losses at those levels what test kit are you using?

 

using API test kits

 

Ca is ok. It just means that you will not see allot of growth.

 

Alk is about a point too low for SPS.

 

It could be because of the Alk or it could be because you are causing a micro swing that is too high in the area where you are putting in your new water and thus burning your corals. Going from a 7 alk to a 11-12 alk will cause a burn if the solution is concentrated. The reason the other corals are not affected is that the solution dilutes enough before it hits them.

 

that could explain some of the losses but the acans and birdsnest i have lost were on the other end of the tank from where i put in my water change water. i usually add the new water into my hang on back filter but there are corals right under the output of that filter that are thriving.

 

I think you might have hit the nail on the head with this suggestion....do you dose in a high flow area or in the same area each time? Seems like if you did and if it was a low flow area, the corals in that area are getting blasted with huge swings in not only Ca but Alk.

 

Just wondering though since you've said that you have experienced not only STN, RTN, but also losses with LPS as well. Have you noticed the tips on any of your SPS turning really white...not growth tip white but Alk burn white.

 

dont know exactly what alk burn would look like but no i havent seen the tips of anything turning really white, its just that there would suddenly be a white patch on my montis and then it would spread from there.