[Rockstar]

I know that as long as its stable it should not be a problem but what readings do you all have.

Ive switched to a Salifert kit as i hear they are the best and my Dkh is higher than the previous test Kit. it used to read between 8 and 9

My readings are as follows

Ph 8.2
Calcium 420
Magnesium 1310
Dkh 11.5

Your comments would be much appreciated.
Rocky.

[bobba fett]

Between 8 and 11 I believe, again stability is best

[BOM8ER]

On an SPS reef I find 10 DKH to be a good level but as already stated stability is very important, the rest of your readings look good but the only thing I would buff is your Magnesium, 1350 - 1400 is the benchmark

[lindsay]

I try to stay around the mid 9s.

[Tony B]

Double figures around 10 to 11 dkh

[Social D]

Im at 7 but normally it was 8ish

[TrevC]

Mine sits around 10/11

[Social D]

If natural seawater has a kh of 7 to 8 why is it some run levels at 10+?

Ive not seen any benefits of running higher levels of kh in the past and tbh no benefits of lower, Alk burn is often is asociated with high kh
does this not concern anybody.

Im not claiming this but sinse my kh has dropped to 7/8 from higher levels my die back has stopped completely, I did begin to wonder if excessive vodka dosing was to blame but maybe keeping kh levels at a more natural level or possibly correct levels suits acropora better.

Maybe a longevity test with reef tanks and associated kh levels might give some answers towards success .. just a thought

[jason@jasonsaquatics]

Maybe its a problem with the Vodka lowering the Nutrients in the system .I know that you have to keep the Dkh low in a z vit system maybe this is the same is carbon dosing .

In my old system my Dkh was most of the time kept at 11ish and i never had any problems with die back and all acros seemed well happy with well good growth .A lot of others guys are running theres well over NSW and they to have no problems and again good growth.

Myself i think maybe its a problem with the excessive carbon dosing


jas

[chriss]

I aim for around 9 dkh, that way if it falls unexpectedly I'll pick it up before it goes too low. I also assumed that another reason may have been that since a tank can be less stable ph wise than the sea that a slightly higher dkh buffers any ph shifts better.

Like Tim, I've seen no difference in growth between running at around 8 dkh or 10+dkh for periods of several months.

Chris

[Simon Garratt]

Quote

If natural seawater has a kh of 7 to 8 why is it some run levels at 10+?

Its generally a recommendation based on the fact that in an enclosed system the effects of the biomass on pH values and the density of potential coral growth has a far greater effect on stability than that biomass would have on the surrounding water in the wild.

Having a slightly elevated level counters this effect.

Its not unusual for a great many systems to take up at least 1DkH per day without constant buffering, This has a knock on effect with pH stability allowing a wider and wider 24/7 drift rather than a consistant drift. Admitedly lagoons can be quite variable dependent on several factors, but the front reef and back reef areas arnt generally subject to such wide changes.

Its basically a case of accepting and countering the differences between small volume stability (our tanks) and large volume (the ocean).

[Tony B]

Simon Garratt, on Sep 11 2009, 10:02 AM, said:

Its generally a recommendation based on the fact that in an enclosed system the effects of the biomass on pH values and the density of potential coral growth has a far greater effect on stability than that biomass would have on the surrounding water in the wild.

Having a slightly elevated level counters this effect.

Its not unusual for a great many systems to take up at least 1DkH per day without constant buffering, This has a knock on effect with pH stability allowing a wider and wider 24/7 drift rather than a consistant drift. Admitedly lagoons can be quite variable dependent on several factors, but the front reef and back reef areas arnt generally subject to such wide changes.

Its basically a case of accepting and countering the differences between small volume stability (our tanks) and large volume (the ocean).

^^^ Well put by Simon ^^^

Social D, on Sep 11 2009, 02:04 AM, said:

If natural seawater has a kh of 7 to 8 why is it some run levels at 10+?

Tim,

We all know anything mechanical will fail, at some point.

I assume you're running a CA reactor? Considering you're running at 7dkh, what would happen if the re-circulation pump failed? Or the water input pipe blocked? Imagine if this happened when you were away for the weekend. With a Dkh of just 7 there is very little reserve in the system - this is why I run my Dkh around 10-11

Tony

[lindsay]

We run around 9 because its betwean the 8ish they were kept in and the 10 to 11 alot of guys keep their tanks at that we sale to.The other point to think about is the test kits that when getting old often read higher than the tank is,i have had this a few times in the past.

[karnivor]

Tony B, on Sep 11 2009, 02:29 PM, said:

^^^ Well put by Simon ^^^



Tim,

We all know anything mechanical will fail, at some point.

I assume you're running a CA reactor? Considering you're running at 7dkh, what would happen if the re-circulation pump failed? Or the water input pipe blocked? Imagine if this happened when you were away for the weekend. With a Dkh of just 7 there is very little reserve in the system - this is why I run my Dkh around 10-11

Tony

I inadvertently left the CO2 turned off on my Reactor and the DKH fell from 10.6 to 8 overnight.

[lindsay]

Dkh levels may also have to be set to a certain level because of the type of system a person is keeping ie,a Zeovit system needs to be around 7 to 8 ish, any higher can cause sps tip problems.Not sure why this happens because i have never looked into it,if this is the case perhaps someone on here knows why it happens?.

[Dave.I]

I keep mine at 8 with a dosing unit and balling light.24 doses over 24hrs for stability.

A vodka overdose would show cyano and possibly milky water but wouldnt normaly cause die back in my experience.

Dave

[jason@jasonsaquatics]

A vodka overdose can cause oxygen depletion and this can and most likely will cause die back .I have put up somewhere on the forum a link to an article from the glass box site that will run you through the problems with carbon dosing and the overdosing problems


jas

[lindsay]

I suspect that the 7 to 8 dkh on a Zeovit system has more to do with the way the reactor and its contents work.

[Social D]

Lots of good reads here

http://www.zeovit.co...isplay.php?f=76