Is alk 6.4 dhk to low for sps?

[MichaelReefer]

Like the title says is the alk level too low for sps. I have some stylo’s that are doing good but most of the other sps kinda don’t do much of anything and a couple have slowly perished. Since I’ve been checking with “Hanna” it’s remaind pretty much betweeen 6.3-6.8. I have a 40b with 20 sump and do 5-10 gallon water change biweekly.

Yes. I run 9.0.

 

[Timfish]

You might find these an interesting read. Corals in Palau's Nikko Reef may live in waters with alkalinity as low as 5.3 dKH or 95 ppm:

Palau’s Improbably Healthy Coral Reefs

Why acidic waters haven’t killed Palau’s vibrant coral could help save many reefs from catastrophe.

www.pbs.org

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013GL058489

 

[fnlyreefready]

Being from the UK I se comments regarding Instant Ocean Reef Crystals, mostly seem to lead to issues in tank stability. I'm glad that we don't seem to have this salt very widely over here, as to me it would appear this "cheap beginner" salt would be the cause to many problems and tbh I don't know why it's still being produced or purchased... Well I guess it's a cycle of its being produce because people are buying it, I don't get why a shop worth its salt (excuse the pun) would recommend it. I know there are people that swear by it but most expert reefers may have started with it have found alternative salts and move away and when they do have higher success. While I'm not saying it's the reef crystals causing the low Alk, I'd say get something different, slowly switch over by doing smaller changes and gradually increase the amount of new water until you reach your desired or normal water change amount.

I use reef crystals and have 0 issues. The only thing I will say is the alk comes very high for most salt dates

 

[Luna Lagoona]

I have a smaller tank (25g) so I will be shooting for having a 9 alk but so far have been around 5.9 to 6.9 with mainly LPS that have grown to consume it before I really started testing my parameters.

I was just doing a 20% water change religiously but I didn't realize how much consumption was a factor for me.

You want to look for stability instead of chasing numbers. My 160g system run on 6.4 alk and 380 cal.

To be honest your post is the reason I am commenting!

I just had to say this is SUCH a nice mixed (SPS Dominant) reef! Well done!

Here's my little "Low alk" lagoon! (soon to be fixed though!