Rapid Growth of SPS using pH as a tool

6 posts in this topic

Yes, I have been out for a while and I am sure everyone will give me grief for it, but I found a few things in the last few months I wanted to bring to light in case it helps someone in the future with a more stable reef tank and prevent them from losing frags. So..... This is a lot to read but I couldn't help but share my findings of what caused part of my tank crash when I though everything was great. 


So first question is.....Who here has the most stable pH because I believe I may have stumbled over something that has really changed my SPS growth over the last 2 months when I had my crash and burn? I mean how stable can you keep your pH in a 24 hour period daily? 



Fussion 1 CA

Fussion 2 ALK

IONS- for Mg

FUEL - Carbs

Flarworm Stop- SPS vitamin, precautionary

RG Complete weekly

Tigger Feast weekly

Sea Veggies

Vita Chem bi weekly in SV

Mysis Feast - weekly

Coral Colors ABCD weekly

Strotium every other week

NOPOX whenever needed

Skimmer 24/7


Some signs my tank was going downhill quick, keep in mind Ca was 500 and Alk was solid 8.2:

  1. Corals receding
  2. Corals dying
  3. Coraline growth disolving
  4. Gorgonian holes, lack of opening up, polyps not extending
  5. Leather retracting
  6. Polyps not extending
  7. No SPS growth
  8. Colors were not as brilliant



So heres what I found... 


First of all, I had issues with good circulation and nitrates. It was very hard to keep nitrate in my tank and was having to dose with Flourish Nitrogen. So to resolve the issue, "which I should've did a long time ago going all the way back to MACNA", I went out and bought a pair of APEX Wave Makers and a lot of fish. ALOT...  Then, I started over by making a chart of my dosing schedule and started plotting pH curves, Ca, Alk, Mg, NO2, NO3, and PO4 almost daily again. I was coming in 2 hours early to work and testing some parameters daily, bi weekly and weekly..


Now most of us don't watch the pH but it can tell us a lot about our tank which I ignored for a long time. There are some fundamental processes that take place that are impacted by changes in pH. I found this out when I had my tank almost crash so I spent a lot..... of time rereading trying to figure out what happened. Some of this was due too lack of nitrates from not enough fish, some was from high phosphates, unbalanced water chemistry, unknown precipitation that was taking place, unbalanced loads of O2 vs CO2, etc. etc. etc., and another was lack of calcification due to wide pH swings and too high of Ca with unstable Alk which caused unstable pH and inversely unstable ORPI can't say I know what the perfect pH is but I can say the most stable pH is more important than I thought and we take it for granted with what it tells us behind the scenes. I went from swings of 7.9 to 8.4 daily and paid no attention to now a pH range of 8.07 to 8.12(8.3 being the goal) almost daily. Before I am asked, no pH up/down was ever used or supplemented to stabilized the tank. 


I originally saw the most swing simply due from night and day due to simple photosynthesis and respiration where organisms in the tank were converting CO2 to water, carbs and O2. Biggest swing you typical see is when the lights cycle on or off. wink, wink...   During photosynthesis the process is consuming CO2, and pH rises due to the water becoming more alkaline. Then during respiration, the pH drops and carbs are converted into energy or as we know it lipids and proteins within our SPS

Okay, to break it down in simple terms so I don't lose the newbies, corals have what’s called photosynthetic algae, or zooxanthellae, that live in their tissues. This "ZOO"(just less to type) and the coral are married in a since where the coral protects the "ZOO" with somewhere to live and in return the "ZOO" provides bi products the corals use to make up their skeletons. Going back to my above paragraph, the "ZOO" supply’s the coral with glycerol, amino acids, glucose, and others which in turn the coral uses to make its proteins, fats, carbs in order to make its skeleton or " calcium carbonate". Now think of the polyps you see on the corals, these corals take the food you feed them in addition to the energy from the ZOO and secretes calcium carbonate on its skeleton which in turn grows the coral....


With that being said, if your alk swings a lot, which in turn is seen by your monitoring of the pH(if you tank chemistry isn't properly balanced) this can cause undue stress on your tank as a whole. If the corals become too stressed, the polyps can expel their algal cells and then turns a bright white appearance which is called bleaching. So it doesn't necessarily mean you burnt your corals from too much light which is the most common answer given to bleaching. This bleaching just means "something" stressed it out so bad, it started expelling its "ZOO" and its your job to figure out why.. 


Breaking down just a bit more, the "ZOO" is the pigmentation that gives our SPS colors and can darken up when it consumes to much phosphate and is why you tend to see your colors loose color or turn a brownish color.  The dinoflagellates inside the corals are already slightly yellow but with more phosphates, it cause them to turn a more brownish color by nature. This I was also noticing in my tank but as it turned out my nitrates were low but the phosphates were high. The nitrates weren’t initially high enough for the SPS needs, however because I don’t have a refugium there was no consumption in phosphates in my tank. When you look at higher alkalinity levels in your tank, this means there is more bicarbonate and carbonate in the water, and these also work together as a buffer in the water against larger pH swings meaning they resist pH swings when additional acids or bases are added. So if your running ULN in the tank, your naturally at a lower alk, which leaves you open to the possibility of possible stress to the coral in the event something catastrophic happens with your water chemistry. So basically, the higher the pH is along with stable ALK, the more effective buffering the bicarbonate and carbonate has within the tank.


What I didn’t realize was my Ca was almost always 480 or higher which drifted away because I didn’t check it as often. I used to think 500 Ca was always good but what I didn’t know with Ca so high, this also cause precipitation with the alk which I couldn’t ever get a stable ALK in the tank.

With that all said, I’m not here to say pH swings will make or break your tank. I am simply saying I understand more now of what causes the pH swings and because it is a bit more complicated may be part of the reason some of us never paid it much attention before other than monitoring it from a Calcium reactor. When in actuality the same effect is happening in the tank on a larger scale but harder to determine what exactly is causing it. One thing that is a fact, a huge swing in pH can cause corals and other organisms in you tank to become very stressed. Even a low pH can make it harder to obtain sufficient carbonate to deposit onto their skeletons and if too low pH will cause their skeletons to start dissolving.  I’m sure we have all heard to slowly add alk or Ca in a tank to keep from stressing and part of the reason is because of the amount of pH change in a tank.


Easiest way to think of pH(power of hydrogen) is this, pH is based on a scale of 0-14, with 7 being neutral. 0 being acidic like battery acid and 14 being very alkaline like lye, potassium carbonate or like drain cleaner.

So why do we usually see the pH typically drop along with low ALK?  The normal trend for pH in a reef tank is typically downward, or more acidic from the addition of acids to the aquarium.


These acids could come from either

  1. excess  (CO2) f from inside your home or office from respiration caused by lack of sufficient gas exchange,
  2. nitric acid from biological filtration (nitrification), and
  3. organic acids from metabolic wastes, dirty socks, waste sitting in the sump or
  4.  improper dosing of ALK from the corals conversion of calcium carbonate onto their skeletons.


When the pH in a saltwater system starts to drop, it is an indication that the buffers are getting worn out, and the increase in acidity needs to be corrected.


With it being 2 months into this and basically baby sitting my tanks water chemistry, all of my parameters have stabilized better than ever before. I now see my Gorgonian opening up like never before, full polyps on my SPS, stable alk, and actually seeing improved growth on the corals that survive the crash.


Items that were changed:

  1. Separated F1 and F2 by 15 minutes if dosing on the same hour
  2. Moved alk dosing times around on schedule to balance daily Alk levels and 24 hr pH levels
  3. Reduced Ca dosing to 440
  4. Maintain ALK to 8.5 through out the day
  5. Use ORP as a sign to change socks or clean sump
  6. Follow documented schedule to the tee for addition of supplements and refrigerated food
  7. Back to direct coral feeding schedules



I know this was a lot to read, but it helps anyone from going through what I went through and preventing loss of prized corals, time and money spent then it was worth it to write what I found in my testing over the last 2 months. 


 I'm not out of the woods just yet due to my tank having cyano but the corals and my tank seem to be back on track.... Hope this helps someone out there not make the same mistake..


One last thing I forgot to add in my original post, once my pH was stable across the board, I was able to raise my pH by adding a CO2 scrubber to the skimmer.  After 2 weeks on the scrubber @ 8.3 pH, I am finally starting to notice a slight drop in Ca and Alk which means calcium carbonate is forming faster within the SPS. Now the challenge will be to find where CA and Alk dosing level stops and to make certain the CO2 media gets changed before it exhaust itself. Another maintenance to keep up with



Edited by Mobilecal

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Great write up!  My 30g is only about 3 months old at this point, but I have been trying to keep an eye on my pH.  I don't chase pH numbers, but I definitely check it daily.  I haven't noticed any major instability in my tank other than recently when I dosed too much Mg causing my Ca to go high and my alk to go too low. I have since adjusted my parameters after a water change and they've been holding steady again for the last couple of days.  My pH usually fluctuates from 8.2 to 7.96.  I don't have an apex to track trends on a graph, but I do keep an eye on my DA Reefkeeper readout.

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I've only used ORP when I was running ozone, I still have the probe but never noticed any correlation between ORP and a dirty sump. So, I looked at my controller's history and ORP jumped from 375 to 475 around the time I cleaned my sump last month. Total drain, cleaned all pumps, heaters and scraped all the filter feeders off the glass, the tank had been ignored for awhile. Interesting observation, I do agree that stability is the key to success.

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I only use the ORP to tune my skimmer in relation to looking at the pH. Ive always notice when doing a water change my entire range of ORP, both low and high levels will be naturally low in range of each other.  During feeding I can see it go low, during skimming I see it go high. Both of which are opposite to each other when the lights are on or off and based on the level of pH. I just used it to give me more of an indication or trend to watch in the event I have an upset to determine whats wrong... simply, its a relationship between oxidizers and reducers and the volume of your tanks ability to break down decaying organisms or dying things in your tank. 

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Thanks Eric...


Lets just say I went through ALOT of Reef Foundation testing... I forgot to add when my red planet tenuis starting bleaching it got to almost 1.5 inches from the tips of one side of all branches. Within about 2 weeks I had my tank basically pH balanced, not tweaked and the bleaching actually stopped with no change in light schedule or relocating the coral. As of today it has recovered completely except about 1/4" and I now can see red polyps on the tips. Just thought I'd throw that in there to..


Also I may have to run a line from outside to my skimmer to get the pH a little higher since everyone breaths so much hot air in the office the volume of hair increases with CO2


Simple enough test for you to try yourself....,1. turn your skimmer on and off(if its in the sump and your probes are downstream of it), or 2. add a line from outside to your skimmer, or 3. open an O2 tank slightly above the skimmer line and you can watch for yourself pH change over just 10 minutes. 


Some good reads if your interested for you lurkers:




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