masterbuilder Posted May 16, 2008 Share Posted May 16, 2008 Sounds like my tank.....does nearly the same thing. Link to comment
bdare Posted May 17, 2008 Share Posted May 17, 2008 I wonder if you brought you Mg up if you could get your alk higher?? I generally keep my Mg around 1400 and my Ca is 480 Alk - 10dkh. Link to comment
Sexy Shrimp Posted May 17, 2008 Author Share Posted May 17, 2008 Hmm I suppose it is an idea. I thought 1290 was OK for Mg? Link to comment
bdare Posted May 17, 2008 Share Posted May 17, 2008 Hmm I suppose it is an idea. I thought 1290 was OK for Mg? 1290 is definitely fine if you are keeping the levels in you tank at NSW. If you're trying to elevate all your levels (alk 10, Ca 450) you may also need to keep Mg above NSW. Link to comment
Sexy Shrimp Posted May 18, 2008 Author Share Posted May 18, 2008 Still seems steady at KH 8, Ca 460, Mg 1290, pH 8. Gonna go out an get some supplies to dose for alk and Mg properly Link to comment
Sexy Shrimp Posted May 18, 2008 Author Share Posted May 18, 2008 Just done my weekly W/C and have dosed both alk and Mg. I have got my Mg up to 1470 and unfortunately my KH to 14 eeek. I am not too worried about it as my pH seems OK and it hasn't made my Ca level change. Is it low alk where Ca precipitates? Before After pH 7.8 8.2 KH 8 14 Mg 1290 1470 Ca 460 460 Link to comment
bdare Posted May 19, 2008 Share Posted May 19, 2008 Usually when you try to push all the numbers TOO high is when precipitation occurs. It's even more likely with eleveated Ph. Link to comment
Sexy Shrimp Posted May 19, 2008 Author Share Posted May 19, 2008 Well 12 hours on a no precipitation. pH 8.2 Ca 460 KH 12 Mg 1470 Link to comment
bdare Posted May 19, 2008 Share Posted May 19, 2008 Nice! Those numbers look real good. Now if I could just keep my OWN stinking tank there! Link to comment
Sexy Shrimp Posted May 19, 2008 Author Share Posted May 19, 2008 I've not kept it there yet Seems like I have found what I need to dose per day though... Luckily it was easy (although I am loath to dose its cheaper than water changes!!) Link to comment
MrAnderson Posted May 20, 2008 Share Posted May 20, 2008 i'm sorry and maybe i missed it but i can't really interpret your data without pH readings taken at lights-out and lights-on; that's the only proper "pH measurement" of a tank. all tanks have a diurnal pH swing, some bigger than others, and if you take readings at different times of the day it is very typical to get different readings. this is perfectly natural, the pH on a natural reef can have a diurnal swing as well, from about 7.8 at night to 8.4 during the day. otherwise i think you're just chasing a moving data point. and why do you keep your carbonate and Ca so unnaturally high? Link to comment
Sexy Shrimp Posted May 20, 2008 Author Share Posted May 20, 2008 i'm sorry and maybe i missed it but i can't really interpret your data without pH readings taken at lights-out and lights-on; that's the only proper "pH measurement" of a tank. I test at midpoint of lights on. Same time every day. and why do you keep your carbonate and Ca so unnaturally high? The salt mix mixes to calcium 460, KH 12 which although high, is in balance. I would rather have it high and in balance than swinging everywhere and out of balance. Link to comment
bdare Posted May 20, 2008 Share Posted May 20, 2008 L34NN3, Your numbers will not swing all over the place if they are not "in balance". The "balance" is the fact that for every 1dkh your tank drops only 20ppm of calcium will be consumed. The reason this is even discussed is for finding "balanced" 2 part additives .However for non-chemistry people like myself this becomes somewhat irrelevant with the advent of online chemisty calculators. The balanced numbers you are referring to are just for reference. Just because your numbers don't fall within that scale will not cause precipitation. Ben Link to comment
MrAnderson Posted May 20, 2008 Share Posted May 20, 2008 I test at midpoint of lights on. Same time every day. then your original pH (8.0) actually sounds about right for midday, and it might not have been "low". most tank's pH will increase another 0.1-0.3 pH from midday to lights out. it really would be most informative for you as well if you determined your diurnal pH swing. if you're at 8.2 now at midday, you might be hitting 8.5, 8.6 at lights out, where before you might have been getting up to 8.1-8.4 at lights out, a reasonable value. but you never know until you check. Link to comment
Sexy Shrimp Posted May 20, 2008 Author Share Posted May 20, 2008 Your numbers will not swing all over the place if they are not "in balance". They were - that was the whole point of the thread in the first place. I couldn't get my pH to stay above 7.8, with it being 8.2 after a W/C. Even just a few days of dosing has kept my pH stable. Also the whole idea that 1dkh drop correlates with 20ppm drop in calcium doesn't happen with my tank - the calcium stays stable with weekly water changes and doesn't drop in relation to the amount that the alk drops. My tank can lose 4dkh over 12 hours but the calcium barely changes... The dosing now seems to have been working and I am much happier with my numbers As a scientist numbers bug me Link to comment
bdare Posted May 20, 2008 Share Posted May 20, 2008 You keep jumping to Ph which isn't really accurate. If you alk is moving that's one thing, but I would not base my alk dosing on my Ph. That methodology is how a lot of people who are new to the hobby get thier alk WAY too high. If you alk is high enough and your Ph is still low then it HAS to be a CO2 issue. It is also true that some tanks consume more alk than Ca... mine does the same. As I've stated though... the fact that Ca and Alk are out of balance alone will not cause them to swing drastically. Ben Link to comment
Sexy Shrimp Posted May 20, 2008 Author Share Posted May 20, 2008 If you alk is high enough and your Ph is still low then it HAS to be a CO2 issue. My CO2 is the same as it was before I had the alk swing problems when the pH was a stable 8.2. The only two variables are the alk and the pH. A difference of 4 in the alk within 12 hours appeared to be the cause of my pH swing. My pH seems to be a steady 8.2 now. The only things I have altered are the alk and the mG through dosing. I did chemistry as one of my majors (UK equivalent) at college and I work in a pathology lab with part of my job being biochemistry. I am aware how chemicals interat - even on a cellular level. Params before dosing after 4 hours lights on pH 8.2 DKH 11 (fallen sl) Ca 460 Mg 1450 (fallen sl) CO2 within 1sd of normal (I don't normally test this early in the day) - this is an arbitary value I use from results obtained using a blood gas analyser within the laboratory. I do not have a normal range but I have esablished a mean and as long as my results are within 1sd of this I am happy I seem to be getting major corraline growth this week and I not sure whether this precipitated the fall in alk or is as a result in me dosing. I also have 3 buds of calciferous macro algae (can't remember the name - mental note) forming that looks pretty cool. Link to comment
The Propagator Posted May 20, 2008 Share Posted May 20, 2008 Do you skim aggressively ? Some times for reasons unknow to us still over skimming can effect PH and drop it. Some say its a myth some say its true. My self I know its true because it happened to me with my old 20L. Ben's right about the rapid consumption of ALK in certain tanks. It happens. Mostly happens due to growth spurts in SPS and LPS though. Or a large bioload in general. I went nuts trying to figure out the same problem and it was due to all my LPS and SPS taking off. In my HEAVILY stocked 100 frag tank the ALK drops right about 1-1.5 dkh per day. Calcium drops about 30ppm - 35ppm about every 3-4 days. Link to comment
bdare Posted May 20, 2008 Share Posted May 20, 2008 Its the salt. Switch back.Reef crystals suck ass. "Wut choo tawkin' bout Willis"? What's wrong with RC? Link to comment
MrAnderson Posted May 20, 2008 Share Posted May 20, 2008 CO2 within 1sd of normal (I don't normally test this early in the day) - this is an arbitary value I use from results obtained using a blood gas analyser within the laboratory. I do not have a normal range but I have esablished a mean and as long as my results are within 1sd of this I am happy wait... what? 1 SD of what? what values are you basing your statistical curve on? blood gas fluctuations are very different from atmospherically-driven swings. aren't most CO2 blood gas assays based on a curve derived from pH and partial pressure of O2? Link to comment
Sexy Shrimp Posted May 20, 2008 Author Share Posted May 20, 2008 wait... what? 1 SD of what? what values are you basing your statistical curve on? blood gas fluctuations are very different from atmospherically-driven swings. aren't most CO2 blood gas assays based on a curve derived from pH and partial pressure of O2? That was why I stated earlier that it is an arbitrary value. I use it only to see if my CO2 is low or high compared to normal. I know it isn't the best way to measure it but it is a guage of variability rather than an actual numerical value. The figures are meaningless but I know if my CO2 is high or lower than "normal" values for my tank. Link to comment
bdare Posted May 20, 2008 Share Posted May 20, 2008 That was why I stated earlier that it is an arbitrary value. I use it only to see if my CO2 is low or high compared to normal. I know it isn't the best way to measure it but it is a guage of variability rather than an actual numerical value. The figures are meaningless but I know if my CO2 is high or lower than "normal" values for my tank. did't you also say you are taking that water from your house to a lab to test it? Isn't it possible that the atmosphere could interact with that water before the test thus skewing your results? Link to comment
masterbuilder Posted May 20, 2008 Share Posted May 20, 2008 I am exhausted just reading this. I don’t mean this in a bad way...but seems like a dog chasing its tail. I have seen you post ALK from 7 to 15. Seems like everything is soooo unstable. I am far from an expert, but there are dozens of stories here by experienced reefers that began chasing parameters so much they ended up with a mess on their hands as well as an empty tank. I know you know what your doing...but...sometimes we all focus on the details and forget the big picture. As a distant observer, I see trouble brewing. MAYBE...dose 1/2 of the alk you think you need every few days and stop testing for awhile. Ya know...let it settle for a few weeks You scientist types would drive a wooden Indian crazy Link to comment
Sexy Shrimp Posted May 20, 2008 Author Share Posted May 20, 2008 did't you also say you are taking that water from your house to a lab to test it? Isn't it possible that the atmosphere could interact with that water before the test thus skewing your results? I thought I said earlier - I take a tubeful and put it "on ice". This is the best way to keep CO2 from varying "in transit". I literally live around the corner from work so its max 10 mins from tank to analyser Why is everyone criticising me dosing my tank? Loads of people have said they had the same problem and nned to dose... I wasn't going to dose originally (see earlier posts) but was told with my Mg low and my alk varying so much it was advisable to dose. I got chewed for not dosing and now I'm getting chewed for dosing. I'm not going to stop testing and dosing as my screwed up hammer (which made me test my water in the first place) is now fully opened up I'm going to stop posting though because the only thing getting screwed up at the mo is my head Will post an update in a week. Link to comment
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