Alkalinity

[pokermagic]

I have a simple question about my tanks alkalinity. My 29g ph is 8.1 and a dKH of 13 with calcium at about 425. I've read that the alkalinity should be between 7-10 dKH. Is mine too high and if so what's the best way to lower it. I have coraline alge growing but has seemed to slowed down. Thanks.

[Jimbo]

Add some magnesium to your tank. Epsom salt you can get it at most pharmacies. I ended up adding about 5 tablespoons to my 40g and the coraline took off. Awaiting salifert test kit for magnesium. I get conflicting results with my alk strips. It says' my dkh is at 26 LOL But everything looks good. I have added a ton of "Reefbuilder" seachem and sps's have started growing better. some of the kits for alk test for Ca carbonate hardness and some test for general cargbonate hardness and some incorporate both. Hopefully I'm correct about this, but maybe some else can clear up this issue.

[tdwyatt]

Originally posted by Jimbo
Add some magnesium to your tank...

Hold off on adding anything until you test both your magnesium and your salinity. Magnesium can vary based solely on your salinity. If your salinity were 33PPT, then your Magnesium will be low by 9% or a total variance of 108 mg/l (from a normal Mg of 1300mg/l). High Alkalinity has many causes, and based on your discription, I would tend to think that it is your Ca that is off (i.e., reasonable alk with decreased growth of coralline...). We need more info about what your husbandry for the tank is, what your total water column parameters are, how you currently supplement your system's calcium and alkalinity (and how much you use), how you've determined the alk and a time frame for your values, along with a description of your system's setup. It can be anything from Mg levels (as Jim has suggested) to poor circulation resulting in an accumulation of alkalinity over time to bad test kit results. Calcium and alkalinity go hand in hand as a balanced supplementation, so the addition of one usually requires the addition of the other.

Give us some more info about your system, there are many here that will be able to guide your efforts.

In addition, unless you have a large number of stony corals, your alk is not that bad...

[Jimbo]

Originally posted by Jimbo
Hopefully I'm correct about this, but maybe some else can clear up this issue.

Thanks Tom

[mapster]

we will need to know how you are buffering your ca & alk levels and if and how you are buffering your ph.

I wouldn't say your alk is at a dangerous level, so any correction can be made gradually. stop using kalk (for now) if you are using it, this will only worsen the problem. Instead you may want to dose just calcium chloride, enough to maintain your current calcium level and let your alk drop gradually.

A water change may help as well.

I would lay off using any type of "seabuffer" you might be using as well.

HTH
MAP

[pokermagic]

Thanks for all the help... Here's my tank set up. It's a 29 Gallon 30W x 18H and 18D with a built in overflow on the right back end of the tank so it's less than 29 gallons... more like 27-28. The overflow goes to an old 10 gallon sump which holds about 7 gallons right now. Skimming is provided by a CPR Backpack.

Circulation is provided by a Mag 3 (350 gph) back to the tank, a Aquaclear 402 (270), and another small powerhead (100 gph).

Lighting is provided by a Hamilton Compact Flourescent (2) 28w 6700K and (1) 28w acintic bulbs on for 12 hours with the acintic on 1/2 hour before and 1/2 hour after the 6700k's.

I have a plenum under about 2 inches of crushed coral and a layer of 1-1 1/2 live sand. Live rock is about 20lbs fuji and should be adding somemore soon. As far as livestock, I have 1 ocellaris, 1 blue damsel and an orange goby... Plenty of astera snails (14) and blue legged hermit crabs (9) and a emerald crab. My corals are a seabe anenome, closed brain coral, bubble coral, pulsing xenia and a leather.

Water parameters...
78 degrees, 1.025 salinity, ammonia 0, Nitrite <.3, Phosphate .5, CO2 3.7, ca 425, dKh 14, PH 8.1.

I add Seachem's Reef Kalkwaser, I drip at night about 2qts a night with the rest coming from another resivor for top-off of which has Kent's conentrated iodine and molybdium/strontium. Additionally I use Kent's reef carbon occasionally.

I hope this helps... Thanks.

[Jimbo]

What test kit are you using for alkalinity?

[tdwyatt]

and in addition to Jim's question, what are the results of testing a batch of freshly made Instant Ocean ASW adjusted to 35 PPT salinity (SG 1.026 at 80F) with your alkalinity test kit (do more than 1 test of it)???

[Robbie]

In a tank that size the best way to get your alk and calc in balance again would be a series of water changes, Maybe 20%
every other day for a week. You will never get it right dumping this and that in to the tank. Just do the water changes and take your test kits and water sample to a pet store and verify your results.

While you are doing the water changes do not add in chems or kalk to the tank.

Robbie

[tdwyatt]

Originally posted by Robbie
In a tank that size the best way to get your alk and calc in balance again would be a series of water changes, Maybe 20%
every other day for a week. You will never get it right dumping this and that in to the tank.

Actually this is prolly the best answer in a small tank, as it will also replenish trace element problems and reestablish the proportionality of your conservative elements as well. After a few weeks of every 4 or 5 day water changes, establishing a balanced additive replacement for your calcium and alk (like kalkwasser) should give you what you need, especially if coupled with regular 10% water changes.

Good call Robbie! No sense in reinventing the (water)wheel...

[Jimbo]

Although I see the logic in tdwyatt and magics analysis of the situation. In a small tank certain trace elements can get used up rather quickly. It's important to replace some of the major elements such as sodium, Magnesium, Calcium, Strontium, Boron, and many less elemental substances.

Water changes can be the simplest answer, for optimum growth of your inhabitants more study and analyasis needs to be done. Sometimes this is just plane guesswork. Many of these substances can be replaced by a Ca reactor. Thats if you use standard crushed coral for your medium. Your dissolving what elements the corals needs in direct proportions.

Water changes can definitly replace some of the minor elements. But in my observation such things like magnesium are best monitored. Along with a broad spectrum trace element additive used with reservation, it's easy to overdose a small system the same as not providing enough of another element. People with larger tanks with 120+ gallons don't see the minor trace element problems to such a degree.

Although I can't give any direct recommendations here, it really depends on the types of creatures you keep. So for now water changes are your best bet But not nececcarily the best solution. Many of us over the years have learned by observation of you inhabitants. Certianly my use of magnesium is guess work / vs. observation. I just kept adding it (slowly) until my coraline algea started growing, slowly over a few weeks. Then stopped it's addition. I'm sure I'm at the high level, but polyp extension is great, to me just one indicator that things are right. I have ordered a test kit for this element, since overdosing can cause serious side effects.

I guess it's sometimes a matter what works for you. I like seachem products for one they told me they only use food grade additives and secondly they don't throw in a bunch who knows what stuff like kent does.

It's not impossible to dose the correct amount of additives. I found Seachems reefbuilder to be a fairly safe product. It keeps your Ph fairly stable, no matter whether you abuse it or not. I also use reefadvantage, but my Mag levels seem to be depleted more quickly than the percentage provided by this product. I do have and use salirfet's calcium test kit.

Personally don't like to do the kalkwasser thing. Have had to many swings in the past and poor coral growth. But did not use reefbuilder then. It may be able to make your system less susceptable to carbonate inballances.

Anyway I'm not trying to takeaway from doing partial water changes. Just that in small systems that additives are more crucial than in larger systems, or just more water changes are neccessary.

[pokermagic]

Sounds like the majority is to make some water changes... I'll do that and see what happens... Thanks for all the help.