Low plant LST - possibly stunted

if DLI is 46 with no added co2 to atmosphere, then it's probably in part your light.. it's a bit too intense. if you are using a phone app, it's possible it's just an inaccurate reading too. phone apps absolutely cannot accurately measure umol/s of various wavelengths of light. all it is doing is converting lux, which also has a problem because the phones camera is not so directional, lol... so it reads light from a very wide angle as opposed to what hits it straight on.. which is what real lux or quantum meters are designed to do. easy to rule it out... how tight are the growth nodes ("internode" length)? if fine, the light is no issue. If too tight on anything growing vertically, consider raising light relative to severity tightness or dim etc. Just eh opposite if anything stretches... same procedure as any other time in grow. Extreme LST can stall a plant. you will usually see some 3-fingerd leaves accompany any lst stress that goes about some 'threshold' for that plant... genetic variety exists in this respect. I've bent plants horizontal early and had no issues. i've ben plants over horizontally and had some funky growth. The growth doesn't necessarily stop.. more often it is just spread out more evenly before, therefore is an illusion it has slown down. Initial axillary buds takea second to really kick into gear as far as what our eyes see. Cellular growth ramps up exponentially. coco isn't magic, btw. if you want a similar water capacity:air ratio with soil you want to 50% of substrate to be perlite or similar. Not too chunky that it impedes root growth. Preferably not large chunks fo wood chips, for example. proper drainage and o2 penetration is the same regardless in this context and should have similar root growth, therefore similar growth above ground. coco holds 2/3rds teh volume of water ethat soil typically does... you can see why the suggested ratios are 70/30 for coco and 50/50 for a likely peat or similarly based soil. (66/33 would be a more precise calculation for coco, but 70/30 is just easier to market and say) coco has a chance of being riddled with salt in any batch.. it can and will hapen eventually. it's a great substrate.. it's just that though.. nothing mystical or magical tha makes it superior. if there seems to be, they are comparing to a poorly run soil grow is all with poor drainage or lower o2 presence in substrate.. flip a coin. that's not a valid comparison.